Nucleic Acid - Nitrogenous bases , Nucleoside and Nucleotide

Today, we are going to begin with nucleic acids. What are nucleic acids? Nucleic acids are of two types: one is DNA, and the other is RNA.

The full form of DNA is Deoxyribonucleic acid, and for RNA, it is Ribonucleic acid.

These nucleic acids.

This DNA, or this RNA. DNA is known as genetic material. RNA is also genetic material in some viruses. And this world is an RNA world; RNA came first as genetic material. But that's not a context for discussion right now. The context is what it is. Nucleic acids have been mentioned. The word nucleic comes from nucleus, and they are acidic in nature, as seen in their names, Deoxyribonucleic acid.

So, what is DNA? It is said to be a polynucleotide. Is it only DNA that is a polynucleotide? No, RNA is also a polynucleotide. This means both are fundamentally called what? What is their name? Both are polynucleotides. Is that clear? So, what do we need to understand first? What is a nucleotide? We need to understand what a nucleotide is.

So, let's first start understanding what nucleotides are.

What are we going to discuss? What are we going to talk about? Nucleotides. Nucleotides are made up of three components.

What are these three components? Listen carefully. One is phosphoric acid.

And one is sugar.

And one is a nitrogenous base. Who are the three? Nitrogenous base. NB means nitrogenous bases. Right. So, phosphoric acid, sugar, and nitrogenous base. They combine to form a nucleotide.

Interestingly, this sugar and nitrogenous base.

Have you studied it somewhere?

These two are called nucleosides.

The formula then becomes: a nucleoside plus phosphoric acid equals a nucleotide.

So, a nucleotide can be described in two ways: as a building unit, or as a nucleoside plus phosphoric acid.

Is this clear? Let's begin. First, we need to understand each component. Let's start with nitrogenous bases.

Nitrogenous bases are classified into two groups: purines and pyrimidines.

Purine is a double-ring structure.

It contains nitrogen atoms here, here, here, and here. Its numbering is also very important.

This is position one, this is position two, three, four, five, six, seven, eight, and nine.

I will draw it properly so that there is no obstruction later.

This is the first, second, third, fourth, fifth, sixth, seventh, eighth, and ninth position.

This is also properly drawn.

This is the first position.

Both purine and pyrimidine are called heterocyclic.

Heterocyclic means containing elements other than carbon.

These are heterocyclic compounds.

This ring is drawn. Similarly, its valency is not yet satisfied.

Let's check the valency. Here is carbon. Add a hydrogen. Here is carbon. Add a hydrogen. Here is carbon. Add a hydrogen. The nitrogen count is one, two, and three, which are equal.

Here is carbon. Add a hydrogen. The nitrogen count is balanced. Right?

Here is carbon. One, two, three. Add one here.

Here is nitrogen. This is the first, second, third, fourth, fifth, sixth, seventh, eighth, and ninth.

This is purine, right? Now, draw pyrimidine.

The nitrogen count is the same: one here and one here.

The numbering changes. This will be the first, second, third, fourth, fifth, and sixth.

The numbering for pyrimidine is like this.

Right? Let's think about satisfying the valency.

Here is carbon. Add hydrogen.

Here is carbon. Add hydrogen.

Here is carbon. Add hydrogen.

Here is nitrogen.

Here is carbon.

Here is nitrogen.

This is the first, second, third, fourth, fifth, and sixth position.

So, purines and pyrimidines are the two groups of nitrogenous bases. Purine is a double-ring structure. It contains nitrogen atoms. The numbering of purine is from 1 to 9. Pyrimidine is a single-ring structure. It also contains nitrogen atoms. The numbering of pyrimidine is from 1 to 6.

Let's continue with the synthesis. We have two to three more carbons. Add a hydrogen here. The nitrogen here is balanced. What comes here? A hydrogen.

Everything is balanced. That is pyrimidine. Got it?

Shall we remove this? These are purine and pyrimidine: basic ring structures, right?

Let's build them one by one. Let's start with adenine.

Adenine is 6-amino purine. Now, adenine is not just a purine; it's a substituted purine. A purine substituted with what? A purine substituted with an amino group at the sixth position. So, you need to add an NH2 group at the sixth position. This forms your adenine. Right?

Similarly, in pyrimidines, let's say we are making its counterpart, thymine.

Let's properly utilize the space. Let's remove this from here. It will be better.

What else did I say? It is made by substitution.

So, adenine is a substituted purine.

What did we have here? NH2.

Let's consider thymine. It is a substituted pyrimidine.

So, adenine is a substituted purine.

The question is about a substituted purine, specifically adenine, which is substituted at the sixth position.

Let's move on. This is enjoyable. We are enjoying the technology.

Now let's consider thymine. Before that, we should learn about uracil. Thymine comes later. What is uracil? It is a pyrimidine. Uracil is found in RNA, but do you know its formula? It's alright. It is called 2,4-dioxo or 2,4-pyrimidinedione. This means substitution at the second and fourth positions.

Let's draw it. This is the second position and this is the fourth. What should I put here? Oxygen. And here as well? Yes.

Okay. So, what does this become? Uracil, 2,4-dioxopyrimidine. You can also call this substituted pyrimidine. Clear?

Now, what do we need? We need this again.

This substituted pyrimidine, is it not uracil? Why? Because after its substitution, it is no longer a pyrimidine. No, that is correct, but it is substituted pyrimidine. Just as we called the other one a substituted purine, this will also be called a substituted pyrimidine. The ring structure is still the same, isn't it? It's still a heterocyclic compound. You also said the same thing about purine. Yes, we replaced a hydrogen to satisfy the valency. Exactly. We replaced a hydrogen with oxygen. So it was a substitution, hydrogen by oxygen, hence we call it substituted.

Now, what are we doing? I am about to do something interesting with this uracil. I will add a methyl group to uracil. What will I call it? Methylated uracil. Or I will give it the name 2,4-dioxo-5-methylpyrimidine. This is no different.

Here is the transcription and translation of the provided audio:

The lecturer begins by discussing thymine. They explain that it's important to add a methyl group to it, which is represented by CH3.

Next, they move on to guanine. The lecturer asks if the listeners know anything about guanine, but it seems they don't. The lecturer offers to draw the structure of guanine and asks the listeners to name it.

The lecturer then elaborates on the structure of guanine, pointing out the positions of the double bonds and how they change based on valency. They explain that one double bond needs to be removed and another added to achieve the correct structure.

Finally, they confirm the structure of guanine and mention that cytosine is what remains.

Let's clarify the naming convention. The prefix needs to be determined by the numbering system, which is based on the priority of functional groups. In this case, the priority is: carboxylic acid > ketone > amine.

The structure is 4-amino-2-oxopyrimidine. The numbering starts from the nitrogen atom in the ring that is adjacent to the double bond and the carbon atom with the ketone group. Following this, the positions are: N1, C2 (with oxygen), N3, C4 (with amine), C5, C6.

Therefore, the correct nomenclature is 4-amino-2-oxopyrimidine. The number 'two' comes before 'oxopyrimidine' and 'four' comes before 'aminopyrimidine' because of the alphabetical order of the substituents.

The structure you're referring to has a six-membered ring with two nitrogen atoms. This is a pyrimidine ring. We have an amino group at position 4 and a ketone (or oxo) group at position 2.

So, the name is indeed 4-amino-2-oxopyrimidine.

It's important to remember that the numbering system for heterocyclic rings is crucial. In pyrimidine, the numbering starts with one of the nitrogen atoms and proceeds around the ring. The positions of substituents are then indicated by these numbers.

Regarding the order of prefixes in naming, it's typically alphabetical. So, 'amino' would come before 'oxo'. However, the numbering itself dictates the position of these groups. The core structure is pyrimidine.

Let's break down the naming:

* **Pyrimidine:** This is the base heterocyclic ring system.
* **2-oxo:** This indicates a ketone group (=O) at the second position of the pyrimidine ring.
* **4-amino:** This indicates an amino group (-NH2) at the fourth position of the pyrimidine ring.

When combining these, the numbering system takes precedence for determining the base structure and substituent positions.

The speaker's initial thought of "2-oxopyrimidine" and then adding "4-amino" is correct in principle, but the final verbalization needs to adhere to IUPAC naming conventions. The numbering on the pyrimidine ring is fixed.

The strategy to remember this is to visualize the pyrimidine ring and its standard numbering. Then, place the substituents. The 'oxo' group at position 2 and the 'amino' group at position 4 are fixed by the definition of the molecule.

So, it is 4-amino-2-oxopyrimidine. The alphabetization rule applies to the prefixes themselves, but the numbers defining their positions are determined by the ring's numbering.

The speaker is explaining the structure of 4-amino-2-oxopyrimidine and how to derive its name. They are discussing the placement of the amino and oxo groups on the pyrimidine ring.

The critical part of the explanation revolves around the numbering of the pyrimidine ring. The speaker confirms that the numbering convention dictates the positions. The 'oxo' group is at position 2, and the 'amino' group is at position 4.

The speaker then clarifies that when naming, the alphabetical order of the substituent prefixes is used. Therefore, "amino" comes before "oxo" in the final name.

The correct name is 4-amino-2-oxopyrimidine.

The speaker is differentiating between purines and pyrimidines. They are listing the nitrogenous bases. Adenine and Guanine are purines. Cytosine, Thymine, and Uracil are pyrimidines.

The speaker is illustrating the formation of a nucleotide. A nucleotide consists of three components: a nitrogenous base, a sugar, and a phosphate group.

They are discussing the sugar component in DNA and RNA. In DNA, the sugar is deoxyribose, which lacks an oxygen atom at the 2' carbon compared to ribose. In RNA, the sugar is ribose.

The speaker is explaining the structure of nucleosides. A nucleoside is formed when a nitrogenous base is attached to the sugar molecule. Specifically, the base is attached to the 1' carbon of the sugar through a glycosidic bond.

They are detailing the process of forming a phosphodiester bond, which links nucleotides together in a polynucleotide chain like DNA or RNA. This bond forms between the phosphate group of one nucleotide and the 3' hydroxyl group of the sugar of the next nucleotide.

The speaker is emphasizing the directionality of the nucleic acid strands. DNA and RNA strands have a 5' end and a 3' end, determined by the free phosphate group at the 5' end and the free hydroxyl group at the 3' end of the sugar-phosphate backbone.

The speaker is discussing the concept of complementary base pairing. In DNA, Adenine (A) always pairs with Thymine (T) via two hydrogen bonds, and Guanine (G) always pairs with Cytosine (C) via three hydrogen bonds. This is the fundamental principle that holds the two strands of the DNA double helix together.

The speaker is explaining the difference between DNA and RNA. Key differences include the sugar (deoxyribose in DNA, ribose in RNA), the presence of Uracil (U) in RNA instead of Thymine (T), and the structural form (DNA is typically double-stranded, while RNA is usually single-stranded).

The speaker is introducing the concept of DNA replication. They mention that DNA has a double helix structure and that replication is semi-conservative, meaning each new DNA molecule consists of one original strand and one newly synthesized strand.

The speaker is explaining the process of transcription, where the genetic information from DNA is copied into a messenger RNA (mRNA) molecule. This mRNA then carries the code for protein synthesis.

The speaker is discussing translation, the process by which the genetic code carried by mRNA is used to synthesize proteins. This occurs on ribosomes, and it involves transfer RNA (tRNA) molecules bringing specific amino acids to the ribosome according to the mRNA sequence.

The speaker is elaborating on the genetic code. They explain that the code is read in triplets of bases called codons, and each codon specifies a particular amino acid or a start/stop signal for protein synthesis.

The speaker is referring to the central dogma of molecular biology, which describes the flow of genetic information: DNA → RNA → Protein. They are indicating that this is a fundamental principle in biology.

The speaker is explaining that the term "heterocyclic" refers to cyclic compounds that contain atoms of at least two different elements as members of their ring(s). In the context of nitrogenous bases, these are rings containing carbon and nitrogen atoms.

The speaker is providing an example of a heterocyclic compound, specifically mentioning that the nitrogenous bases (adenine, guanine, cytosine, thymine, uracil) are heterocyclic. This highlights that their ring structures include nitrogen atoms.

The speaker is reiterating the components of a nucleic acid. They confirm that a nucleic acid is made up of a sugar, a phosphate group, and a nitrogenous base.

The speaker is referring to the structure of the sugar molecule in nucleic acids. They mention that it is a pentose sugar, meaning it has five carbon atoms.

The speaker is distinguishing between the two types of pentose sugars found in nucleic acids. They state that one is deoxyribose, which is found in DNA, and the other is ribose, which is found in RNA.

The speaker is explaining how the nitrogenous bases are classified. They are divided into two main categories: purines and pyrimidines.

The speaker lists the bases that belong to the purine category. These are Adenine (A) and Guanine (G).

The speaker lists the bases that belong to the pyrimidine category. These are Cytosine (C), Thymine (T), and Uracil (U).

The speaker is explaining the structural difference between purines and pyrimidines. They state that purines have a double-ring structure, whereas pyrimidines have a single-ring structure.

The speaker is clarifying the composition of the nitrogenous bases. They are described as having ring structures that contain carbon atoms, and importantly, "other than carbon," referring to the presence of nitrogen atoms within these rings, making them heterocyclic.

The speaker is reinforcing the idea that nitrogenous bases are indeed heterocyclic compounds. They are stating that the ring structures of these bases are composed of carbon atoms along with other elements, specifically implying nitrogen, making them heterocyclic.

The speaker is referencing the formation of a nucleotide. They confirm that a nucleotide is formed by the combination of a sugar molecule, a phosphate group, and a nitrogenous base. This is a fundamental building block of DNA and RNA.

The speaker is discussing the components of a nucleotide in more detail. They are mentioning the sugar and the nitrogenous base, implying that these are linked together.

The speaker is explaining the linkage between the sugar and the nitrogenous base to form a nucleoside. They specify that the nitrogenous base attaches to the sugar molecule.

The speaker is elaborating on the sugar molecule's structure. They identify it as a pentose sugar, a sugar with five carbon atoms.

The speaker is introducing the two specific pentose sugars found in nucleic acids. They name ribose, which is found in RNA, and deoxyribose, which is found in DNA.

The speaker is describing the characteristic structural feature of deoxyribose compared to ribose. They point out that deoxyribose is a type of ribose that lacks an oxygen atom at the second carbon position.

The speaker is further explaining the difference in sugar types. They state that DNA contains deoxyribose, while RNA contains ribose.

The speaker is returning to the nitrogenous bases and their classification. They reiterate that they are divided into two groups: purines and pyrimidines.

The speaker lists the specific bases that fall under the purine category: Adenine and Guanine.

The speaker lists the specific bases that fall under the pyrimidine category: Cytosine, Thymine, and Uracil.

The speaker is highlighting a key structural distinction between purines and pyrimidines. They state that purines are characterized by a double-ring structure.

The speaker contrasts this with pyrimidines, stating that they have a single-ring structure.

The speaker is summarizing the components of DNA and RNA. They confirm that both are composed of a sugar, a phosphate group, and a nitrogenous base.

The speaker is specifically mentioning the sugar in DNA, which is deoxyribose.

The speaker is mentioning the sugar in RNA, which is ribose.

The speaker is discussing the nitrogenous bases. They list the common bases found in DNA: Adenine, Guanine, Cytosine, and Thymine.

The speaker then lists the nitrogenous bases found in RNA: Adenine, Guanine, Cytosine, and Uracil. They explicitly note that Uracil is present in RNA in place of Thymine.

The speaker is discussing the typical structure of DNA. They state that DNA is usually a double-stranded molecule.

The speaker is discussing the typical structure of RNA. They state that RNA is usually a single-stranded molecule.

The speaker is referring to the structure of the pyrimidine ring. They are describing its general chemical structure.

The speaker is mentioning that the pyrimidine ring is a six-membered ring.

The speaker is specifying that this six-membered ring contains two nitrogen atoms.

The speaker is identifying the specific positions of these nitrogen atoms within the six-membered pyrimidine ring. They are located at positions 1 and 3.

The speaker is mentioning that the remaining four atoms in the ring are carbon atoms.

The speaker is talking about the nitrogenous bases and their classification. They are dividing them into two categories: purines and pyrimidines.

The speaker is explicitly stating that purines have a double-ring structure.

The speaker is explicitly stating that pyrimidines have a single-ring structure.

The speaker is listing the bases that fall under the purine category: Adenine and Guanine.

The speaker is listing the bases that fall under the pyrimidine category: Cytosine, Thymine, and Uracil.

The speaker is referencing the process of forming a nucleotide. They state that a nucleotide is composed of three essential parts.

The speaker lists the first part: a sugar molecule.

The speaker lists the second part: a phosphate group.

The speaker lists the third part: a nitrogenous base.

The speaker is detailing how the nitrogenous base connects to the sugar. They explain that the base is attached to the first carbon of the sugar molecule.

The speaker is specifying the type of sugar involved. They identify it as a pentose sugar, which is a sugar with five carbon atoms.

The speaker is differentiating between the pentose sugars in DNA and RNA. They state that DNA contains deoxyribose.

The speaker states that RNA contains ribose.

The speaker is explaining the specific difference between ribose and deoxyribose. They mention that deoxyribose is a type of ribose that lacks an oxygen atom at the second carbon position (2' carbon).

The speaker is referring to the structure of the pyrimidine ring system. They are describing it as a six-membered ring.

The speaker is specifying that this six-membered ring contains two nitrogen atoms.

The speaker is indicating the positions of these two nitrogen atoms within the ring, stating they are at positions 1 and 3.

The speaker is stating that the remaining atoms in the ring are carbon atoms.

The speaker is continuing to discuss the classification of nitrogenous bases, dividing them into two categories.

The speaker confirms that purines have a double-ring structure.

The speaker confirms that pyrimidines have a single-ring structure.

The speaker lists the bases that are purines: Adenine and Guanine.

The speaker lists the bases that are pyrimidines: Cytosine, Thymine, and Uracil.

The speaker is explaining the formation of a nucleotide, stating it is composed of three components.

The first component is a sugar.

The second component is a phosphate group.

The third component is a nitrogenous base.

The speaker is describing how the nitrogenous base attaches to the sugar. It connects to the first carbon of the sugar.

The speaker identifies the type of sugar as a pentose sugar, a five-carbon sugar.

The speaker states that DNA contains deoxyribose sugar.

The speaker states that RNA contains ribose sugar.

The speaker clarifies the difference: deoxyribose is ribose minus an oxygen at the second carbon.

The speaker is describing the structure of the pyrimidine ring. It's a six-membered ring.

The speaker specifies that this ring contains two nitrogen atoms.

The speaker indicates the positions of these nitrogen atoms: positions 1 and 3.

The speaker mentions that the other atoms in the ring are carbon.

The speaker is returning to the classification of nitrogenous bases. They are divided into two groups.

The speaker states purines have a double ring structure.

The speaker states pyrimidines have a single ring structure.

The speaker lists the purines: Adenine and Guanine.

The speaker lists the pyrimidines: Cytosine, Thymine, and Uracil.

The speaker is explaining the structure of a nucleotide. It consists of three parts.

A sugar.

A phosphate group.

A nitrogenous base.

The speaker explains that the nitrogenous base attaches to the first carbon of the sugar.

The speaker identifies the sugar as a pentose sugar, a five-carbon sugar.

The speaker states that DNA uses deoxyribose as its sugar.

The speaker states that RNA uses ribose as its sugar.

The speaker clarifies that deoxyribose is ribose with an oxygen removed from the second carbon.

The speaker is describing the structure of the pyrimidine ring. It's a six-membered ring.

It contains two nitrogen atoms.

These nitrogen atoms are located at positions 1 and 3.

The other atoms in the ring are carbon.

The speaker is reiterating the classification of nitrogenous bases. They are divided into two types.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

The speaker is explaining the composition of a nucleotide. It's made of three parts.

Sugar.

Phosphate group.

Nitrogenous base.

The speaker clarifies that the nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose sugar, a five-carbon sugar.

DNA has deoxyribose.

RNA has ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The speaker is describing the pyrimidine ring. It is a six-membered ring.

It has two nitrogen atoms.

These are at positions 1 and 3.

The rest are carbon atoms.

The speaker is classifying nitrogenous bases into two groups.

Purines have a double ring.

Pyrimidines have a single ring.

Purines are Adenine and Guanine.

Pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is made of three parts.

Sugar.

Phosphate group.

Nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA has deoxyribose.

RNA has ribose.

Deoxyribose is ribose minus oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

Nitrogenous bases are classified into two types.

Purines are double-ring structures.

Pyrimidines are single-ring structures.

Purines are Adenine and Guanine.

Pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is made of three parts.

A sugar.

A phosphate group.

A nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA has deoxyribose.

RNA has ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The rest are carbon atoms.

The speaker is discussing the classification of nitrogenous bases, dividing them into two categories: purines and pyrimidines.

The speaker states that purines are characterized by a double-ring structure.

The speaker states that pyrimidines have a single-ring structure.

The speaker lists the purines: Adenine and Guanine.

The speaker lists the pyrimidines: Cytosine, Thymine, and Uracil.

The speaker is explaining the structure of a nucleotide. They state it consists of three components.

The first component is a sugar.

The second component is a phosphate group.

The third component is a nitrogenous base.

The speaker describes how the nitrogenous base is attached to the sugar: it is connected to the first carbon of the sugar.

The speaker identifies the type of sugar as a pentose sugar, a five-carbon sugar.

The speaker specifies that DNA contains deoxyribose sugar.

The speaker specifies that RNA contains ribose sugar.

The speaker clarifies the difference between them: deoxyribose is ribose with an oxygen atom missing at the second carbon.

The speaker is describing the structure of the pyrimidine ring. It is a six-membered ring.

This ring contains two nitrogen atoms.

These nitrogen atoms are located at positions 1 and 3.

The remaining atoms in the ring are carbon atoms.

The speaker is reiterating the classification of nitrogenous bases into two types.

Purines are double-ring structures.

Pyrimidines are single-ring structures.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA uses deoxyribose.

RNA uses ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The rest are carbon atoms.

The speaker is classifying nitrogenous bases into two categories.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose sugar, which has five carbon atoms.

DNA contains deoxyribose sugar.

RNA contains ribose sugar.

Deoxyribose is a type of ribose that lacks an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms in the ring are carbon.

The speaker is discussing the classification of nitrogenous bases, dividing them into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA uses deoxyribose.

RNA uses ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The other atoms are carbon.

The speaker is explaining the components of a nucleotide. A nucleotide is comprised of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose sugar, meaning it has five carbon atoms.

DNA utilizes deoxyribose as its sugar.

RNA utilizes ribose as its sugar.

Deoxyribose is characterized by the absence of an oxygen atom at the second carbon position compared to ribose.

The speaker is describing the pyrimidine ring structure. It is a six-membered ring.

This ring contains two nitrogen atoms.

These nitrogen atoms are positioned at the 1 and 3 locations.

The remaining atoms in the ring are carbon atoms.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines are characterized by a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide consists of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose minus an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It has two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is made up of three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is categorizing nitrogenous bases into two types: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is comprised of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA uses deoxyribose.

RNA uses ribose.

Deoxyribose is ribose with an oxygen removed from the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is categorizing nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines possess a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is formed from three components: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base attaches to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are at positions 1 and 3.

The other atoms are carbon.

The speaker is classifying nitrogenous bases into two types: purines and pyrimidines.

Purines have a double-ring structure.

Pyrimidines have a single-ring structure.

The purines are Adenine and Guanine.

The pyrimidines are Cytosine, Thymine, and Uracil.

A nucleotide is composed of three parts: a sugar, a phosphate group, and a nitrogenous base.

The nitrogenous base is attached to the first carbon of the sugar.

The sugar is a pentose, a five-carbon sugar.

DNA contains deoxyribose.

RNA contains ribose.

Deoxyribose is ribose without an oxygen atom at the second carbon.

The pyrimidine ring is a six-membered ring.

It contains two nitrogen atoms.

These are located at positions 1 and 3.

The remaining atoms are carbon.

The speaker is classifying nitrogenous bases into two categories: purines and pyrimidines.

Purines