Here's the transcription and translation of the lecture chunk:
The lecture is discussing lipids as biomolecules. Lipids are generally insoluble in water. They can be simple fatty acids. A fatty acid has a carboxyl group attached to an 'R' group. This 'R' group can be methyl, ethyl, or a longer chain of CH2 groups, containing between one to nineteen carbon atoms.
For example, palmitic acid has sixteen carbons, including the carboxyl carbon, with the formula C16H32O2. Arachidonic acid has twenty carbons, including the carboxyl carbon. Fatty acids can be saturated, meaning they have no double bonds, or unsaturated, meaning they have one or more carbon-carbon double bonds.
Another simple lipid is glycerol, which is trihydroxypropane. Many lipids have both glycerol and fatty acid components. Here, the fatty acids are esterified with glycerol. They can be mono-, di-, or triglycerides. These are also called fats and oils, distinguished by their melting points.
The speaker then moves on to classify lipids. The categories discussed are fatty acids. Fatty acids have a general formula of CnH2nO2. Examples of saturated fatty acids include palmitic acid (C16H32O2), stearic acid (C18H36O2), and arachidic acid (C20H40O2).
Unsaturated fatty acids, on the other hand, contain double bonds. Examples include oleic acid, linoleic acid, and linolenic acid. In oleic acid, there is a double bond at the ninth position. In linoleic acid, double bonds are at the ninth and twelfth positions. In linolenic acid, double bonds are at the ninth, twelfth, and fifteenth positions. These are all unsaturated.
The speaker clarifies that the term "arachidonic acid" was mentioned earlier and it refers to an unsaturated fatty acid. The number of double bonds can vary. For instance, some have one double bond, others have two, three, or even four double bonds.
Okay, here is the transcription and translation of the lecture chunk into pure, highly readable English:
...how many will reduce? Eight. So the formula will be C20 H32 O2. Right? Yes.
What other important point did they mention? Who is its counterpart? Glycerol.
This was glycerol: CH2OH, CHOH, CH2OH.
Now, combining, these form monohydric, dihydric, monoglyceride, diglyceride, and triglyceride. Yes. Monohydric alcohol and fatty acid. It's actually like this.
So from these, monoglyceride will be formed. No, monohydric alcohol won't work there. If it's monoglyceride, then only glyceric acid will work. That's not correct.
Wax is a different thing. In wax, the alcohol itself changes. You are referring to a monoglyceride. If you are saying glyceride, then glyceric acid will be needed. It won't work without it.
These are two different things. If you are working with monohydric alcohol, this happens in wax. Yes, monohydric alcohol plus fatty acid is not monoglyceride. This, this is your wax.
Right? And what you are talking about here is that glycerol can form three types of glycerides: mono-, di-, and triglycerides. So, these are two different things. It's not necessary for glycerol to be involved in that context.
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These are also called fats and oils, based on their melting point. We know that what is liquid at room temperature is oil, and what is solid at room temperature is fat. Whose melting point is higher, fat's or oil's?
Oil is unsaturated. Why are you making it so difficult? Why so complicated? The substance that is liquid at room temperature, meaning its melting point is low. And the substance that is solid or semi-solid, meaning its melting point is high; that's why you can't convert it to liquid at room temperature.
Oils have a lower melting point, and hence gingelly oil, and hence oil in winter... Can you identify... and hence remains as oil in winter. Can you identify fat from the market? Some lipids have phosphorus and phosphorylated organic compounds in them. These are phospholipids. They are found in cell membranes. Lecithin is one example. Some tissues, especially the neural tissue, have lipids with more complex structures. They are talking about the myelin sheath. Yes, yes, sphingolipid, they are talking about the myelin sheath.
Living organisms have a number of carbon compounds in which a heterocyclic ring can be found. Some of these are nitrogenous bases: adenine, guanine, cytosine, uracil, and thymine. When found attached to a sugar, they are called nucleosides. If a phosphate group is also found esterified to sugar, they are called nucleotides.
I will take a full lecture on this. I am not going into this right now. I want to discuss an interesting point they mentioned later, the point about the acid-soluble pool. Yes, related to lipids. Here it is. We will complete this.
We will begin with nucleic acids, and I will commence with that so that it is also useful for the 12th standard curriculum. We will cover that after the break.
We are switching. We will study nucleic acids later. First, we are transitioning to biomolecule section 9.3. This involves definitions.
There is one feature common to all compounds found in the acid-soluble pool. They have molecular weights ranging from 18 to 800 Daltons.
The acid-insoluble fraction contains only four types of organic compounds: protein, nucleic acid, polysaccharide, and lipid. These classes of compounds, with the exception of lipids, have molecular weights in the range of 10,000 Daltons and above.
For this very reason, biomolecules, which are chemical compounds found in living organisms, are of two types: those which have a molecular weight less than 1,000 Daltons and are usually referred to as micro-molecules. Or simply biomolecules. While those found in the acid-insoluble fraction are called macro-molecules or bio-macro-molecules.
In essence, organic compounds are of two types. Those with a weight less than 1,000 Daltons are found in the acid-soluble fraction. And those that are larger are found in the acid-insoluble fraction. We need to elaborate on what was stated earlier.
The retentate, which is what we had, did not just contain inorganic substances. It contained organic substances with large molecular weights. This is a crucial concluding point that needs to be understood carefully. Who will be found here?
So, here we will find: Organic molecules with high molecular weight. And here we will find: Organic molecules with low molecular weight (less than 1,000 Daltons). And here, 10,000 Daltons. Was this clear? We have now incorporated this into the previous content.
So, we can now say that based on the acid-soluble and acid-insoluble fractions, biomolecules are of two types: macro-biomolecules and micro-biomolecules.
The molecules in the insoluble fraction, with the exception of lipids, are polymeric substances. Then why do lipids, whose molecular weight does not exceed 800 Daltons, fall under the acid-insoluble fraction? This is a fantastic reasoning question.
Even though your weight is less than 800, you are placed in the macromolecule fraction. The reason could be either your magnitude is that large, or your diversity is that great; you are found in so many places. And the second reason is: Lipids are indeed small molecular weight compounds. And are present not only as such, but also arranged into structures like cell membranes and other membranes. When we grind a tissue, we are disrupting the cell structure. Cell membranes and other membranes are broken into pieces and form vesicles, which are not water-soluble.
Even though the weight is less, you form vesicles, like self-like structures, that are not soluble. Therefore, these membrane fragments in the form of vesicles get separated along with the acid-insoluble pool. And hence, in the macromolecule fraction, lipids are not strictly micro-molecules. This is a superb jackpot for studying. Anyone listening or reading this should pay close attention.
What will be the assertion? Lipids are part of the acid-insoluble fraction, despite their low molecular weight.
During separation, there's a lipidacious content like membranes. These form vesicles, which are insoluble.
These are the most important ones. The acid-soluble pool roughly represents the cytoplasmic composition. Macromolecules formed in the cytoplasm and organelles become the acid-insoluble fraction. The acid-soluble pool roughly represents the cytoplasmic composition.
Together, they represent the entire chemical composition of living tissue. In summary, we represent the chemical composition of living tissue from an abundance point of view. Arranging them class-wise, we observe that water is the jackpot.
Water is the most abundant chemical in living organisms. The percentage table is as follows: Water is 70-90%, then comes protein (10-15%), carbohydrate (3%), lipid (2%), nucleic acid (5-7%), and ions (1%).
Okay, we will move on to the next part, which is nucleic acid. Then we will proceed to proteins and other components. For this segment, that's all.