 Okay, so we'll do nucleic acid, nucleic acid, do you have NCRT book with you now? Yeah. Open it. What is the content given in nucleic acid? Just tell me the topic name. Chemical composition of nucleic acid. Okay. Structure of nucleic acid. This is the name. Chemical composition is given then? Bacteria and biological functions. Structure of nucleic acids and biological functions, right? Okay. There are a few structures. What is the name of the structure given? They're given perimidine, cytosine, uracil, thymine, adenine. Okay. Those structures actually you have to again memorize. Sir, is nucleic acid very important from JEE point of view? I don't think it's very important because it is mainly, you know, important for neat experience. Okay. They ask questions and needs. Structure-based questions, replication and all they won't ask in JEE. Structure of compounds that you have, that you should know. Like all names that I have taken know. That you should know. Like the heredity, the genetic code and all that is not required for JEE. So what is important here is to know the structure of the different molecules. Okay. Adenine, guanine, those things like I told you just now, melamine, they have asked number of lone pairs and all. So like that they have, they can give you some name of the compound and integer type questions. Find out the, you know, the lone pair present in thymine, this kind of question they ask. Okay. So structure-based question they ask. Function-wise, they don't ask because that is, then goes to the need, the biology things and all. Okay. So you see here, we'll just finish it. What is a nucleic acid? See, when we talk about the living cells. Okay. These living cells contains nucleoproteins. Okay. Now these nucleoproteins are actually forms by the combination, forms with proteins actually in combination with biopolymers of another type of nucleic acids. Okay. So actually the nucleic acid has, it has, there are two types of nucleic acid. You know that DNA and RNA, right? What is the, like the DNA, what is the full form of DNA? Deoxyribonucleic acid. Deoxyribonucleic acid. Okay. RNA is ribonucleic acid. So the nucleic acid is actually right down. I'll go to the next page here. A structure of DNA and RNA, you can go through the book. It's a complex structure, helical thing and all that you can go through. It is not required here. I won't draw it. It's very complex. It's very difficult to draw also. Okay. That is structure you can go through. What are the link is all there? I'll explain that. So open the book and look at the structure when I, when I was, when I was explaining it. Okay. I'll tell you. So nucleic acids are what these are the compounds, right down, which are made up of compounds, which are made up of proteins and with the polymers of, with the bio polymers of another type of compounds. Okay. So proteins and bio polys are another kind of bio polymers. If they mix, it forms nucleic acid. So the mixture of proteins and other types of bio polymers. Okay. It, it is of two types. Like I said, DNA and RNA. DNA is C ribonucleic acid and RNA is ribonucleic acid, ribonucleic acid. Okay. Next slide. These are basically long chain polymers of nucleotides. Okay. It is basically the long chain polymers of nucleotides. Next slide down, the chemical composition of nucleic acid, chemical composition of nucleic acid. Write down hydrolysis of nucleic acid. Whether you take DNA or RNA, both hydrolysis of this, hydrolysis of this gives pentose, pentose sugar. Hydrolysis gives pentose. This is what you need to memorize. So when you go through the NCRT book, these kind of information, you must keep in mind. Okay. Pentose sugar. Okay. See, there are two types of heterocyclic, nitrogenous base present in this molecule. Like you see the structure, there are two structure. We have the basic thing is pentose and pentose structure. We have already discussed in the fructose thing. Right. So the structure of beta D ribose, which is used in ribonucleic acid, I'll draw here. So I'll draw the structure and write down the name. And it is a three-dimensional structure. Three-dimensional structure. So this bond, this carbon is actually coming towards the observer, this one. This is coming towards the observer. At this carbon, we have OH on the top, H on the bottom. Here we have H on the top, OH on the bottom, H on the top, OH on the bottom, H on the bottom, CH2, OH on the top. This structure is beta D ribose, and it is used in RNA, ribonucleic acid. Another structure you draw, which is the exact structure this you draw here, oxygen. Again, it is coming towards the observer. So the structure is beta D ribose and beta D deoxyribose. Okay. So this one is beta D ribose we have drawn. This one is beta deoxyribose. The structure here we have OH and this side we have hydrogen. This carbon has two hydrogen. Is this a structure given in NCRT? Can you check once? OH, H here. And here we have hydrogen, CH2, OH. It's given, sir. This structure is correct. No, this carbon has two hydrogen. Yeah. Yeah. The name of this compound is beta D ribose, sorry, deoxyribose. Deoxyribose in DNA. These two structures we have. So pentose, actually it has the reference compound is pentose only. Okay. Which has this ring, which exists in these two form in DNA and RNA. Okay. So there are two base actually here. Like I said, the full hydrolysis of DNA and RNA gives a pentose sugar. Okay. Ribose in RNA and deoxy in DNA. Deoxyribose in DNA. Two kinds of heterocyclic nitrogenous base is present in it. Okay. The base that we take. Okay. One is they gives pentose sugar and other one that we get here. So the pentose sugar structure I have drawn two types. And the other one we get on hydrolysis on hydrolysis. It gives two kinds of heterocyclic nitrogenous base. Right down to heterocyclic nitrogenous base. I am just giving you the chemistry aspect of it, the reaction of it. Nitrogenous base. Okay. That we call it as the two nitrogenous base that we get here is purines and pyrimidines. Purines and pyrimidines. And apart from this, apart from this, we also get phosphoric acid. This is what you need to memorize a product. Phosphoric acid. Another important thing here that you already know, we have done this in biomolecules. This is first carbon, right? One, two, three, four and fifth. You're also the same thing. One, two, four and fifth. What you have to keep in mind that C2 carbon in this deoxyribose, C2 carbon does not contain, does not contain OH group. This you must remember. It is not present at C2 carbon. Okay. Now, these two structure you must know, pyrimidine and purines. Okay. Next one, we'll draw the structure of these two. Pyrimidine structure is this. We have a ring, nitrogen. This is the structure of pyrimidine. Alternate double bond. And I'll write down the name here. Pyrimidine. And another one is purine. Purine structure is similar to pyrimidine, which is this. I missed one thing. Here we have nitrogen. Here we have nitrogen. So, pyrimidine, we have this structure. Two nitrogen atoms. Here also we have nitrogen atoms. One, two and three. So, pyrimidine is this. So, this is also pyrimidine. But apart from this, we'll have a five-membered ring here, which has one nitrogen present here. Another nitrogen present here. And these two are attached like this. It's a five-membered ring here. So, we have a double bond here. And then nitrogen we have here. So, one hydrogen this side. This structure is purine. Okay. I'll draw two, three more structure into this because you see what happens in pyrimidine. It has a single heterocyclic ring. Pyrimidine is this single heterocyclic ring. And purines have two ring, fused ring, we can say, heterocyclic, two rings. One is this five-membered ring and the six-membered ring. Two fused ring we have. So, DNA, that deoxyribose nucleic acid, DNA, has the purine base and pyrimidine base. Both base will have in DNA. But not exactly the same molecule, but the base of this, the purine base is adenine and guanine, which is present in DNA. And pyrimidine base is thymine and cytosine, which is present in DNA. But in RNA, it contains uracil instead of thymine. In RNA, we have uracil present, not thymine is not present over there. And it is important to note that there are two key structural difference between DNA and RNA. Okay. DNA contains deoxyribose while RNA has only ribose sugar. That's what we have discussed last page only. The difference between DNA and RNA, the main difference, which is a very important point here. DNA has thymine while RNA has uracil. Okay. So, that's what we will write now. First, we'll draw these structures of adenine, uracil, thymine, guanine. You should know all these structures. Okay. So, with pyrimidine, you have three different base we get here with respect to this. The reference compound is this and with this, we'll get three different bases. The first one you write down from this only, this way, from pyrimidine. The first one is this. We'll have a six-membered ring. Here we have double bond O and here we have double bond O. And alternate double bond is not present in the ring. We have a double bond only here. Okay. So, CH double bond, CH is double bond O and we have H here. And here also we have NH. Trivalence you have to complete. This compound, we call it as uracil. The structure you must remember, name is not enough. Because once they have asked mellamine, they can ask you any one of these structures also. Uracil is represented by the symbol U, capital U. Now, this one, we have cytosine. Cytosine, the difference is what? Instead of this C double bond O, we have NH2 present here. So, the structure is this. This is the structure of cytosine represented by capital C. One more structure we have and that is thymine. Thymine is everything is same with respect to this if you see. But the only thing, only difference is here we do not have one hydrogen, but one CS3 present onto this carbon. The structure is this. Nitrogen we have here. Double bond O, double bond O. Here we have double bond. Here we have CS3, NH and NH. This structure is thymine. That is T. This is the structure of the three bases of pyrimidine, which is present in DNA. Purine, the two base we have that is adenine. The structure is this. We'll draw this structure with NH2 over here. So, the structure will be this. And double bond here. Double bond here and double bond here. This carbon has NH2 and this is attached with one nitrogen. So, we have hydrogen here and double bond here. Hydrogen double bond. This structure is adenine. It is A. And guanine, the structure is just you write down this structure in guanine. Here you write down C double bond O. I'll write down the structure here. This guanine is important. Here we have C double bond O. And here we have NH2. Double bond, double bond, nitrogen, hydrogen here. And this will be as it is. Nitrogen this side, nitrogen this side, and both are attached with double bond CH. Hydrogen we have here. This structure is guanine. That is G. Finish this structure. Let me know. I'll just dictate you two, three points here. Done, sir. Done. So, write down pyrimidine contains, pyrimidine contains a single heterocyclic ring, pyrimidine contains a single heterocyclic ring, while purines have two heterocyclic ring fused together. Purines, sir. Purines have two heterocyclic ring fused together. You see, this is the two ring we have. No, two heterocyclic. This is one heterocyclic ring, another heterocyclic ring. Two heterocyclic ring fused together. DNA contains, DNA contains the purine bases in bracket. You write down adenine and guanine. DNA contains the purine bases in bracket. Write down adenine and guanine. While, sorry, purine bases adenine, guanine, and pyrimidine bases in bracket thymine and cytosine. So, uracil is not present in DNA. Okay. And pyrimidine bases thymine and cytosine. Okay. So, uracil it is not present in DNA. And RNA contains, RNA contains uracil instead of thymine. Okay. RNA contains uracil, not thymine. So, this thymine, it is not present in, not present in RNA. This is another point. Okay. All these compounds that I have written, uracil, cytosine, okay, thymine, all these are bases, right? And it gives nucleoside. This nucleoside of adenine is adenosine. Okay. How do you get nucleoside? Nucleosides are the n-glucosides of purine and pyrimidine bases. Okay. Okay.