NEET PYQ Biomolecules Practice LIVE | Chemistry NEET

Added: 2026-05-11

[00:00:00]the news stream. Today we will be uh looking at some more questions from the neat p values. I hope you are doing good and today I thought of looking at what chapters are currently included in neat and which of the chapters have a reduced syllabus. So you can see the weightage of each of these chapters, how many questions are being asked from each of them. For example, here we are seeing the physics section.

[00:00:30]So you can see the weightage for units and measurement is roughly 6%.

[00:00:36]Then motion in straight line, motion in a plane, so on and so forth. All the chapters are there.

[00:00:44]Finally, we'll be looking at chapters concerning biology.

[00:00:50]So let me try to search where that is.

[00:00:56]So what I'm seeing is solid state and surface chemistry are out of syllabus now also the process of isolation of elements and s block even hydrogen. So these were some of the chapters which student did not like because of too much things to remember but now that they are out of syllabus uh it will make your life easier. So I see one chapter called biomolelecules which is uh related to biology in some sense. So why not let's practice some of these questions from this chapter.

[00:01:35]Although I don't remember the concepts uh as well as I used to earlier but I think it will be a good revision for me and all of you also so that we can learn in this process.

[00:01:50]So I hope the questions are visible to you.

[00:01:56]Okay. So the first question is from neat 2025 and it says sugar X is found in honey is a keto sugar exists in alpha and beta anomeic forms is leotatory.

[00:02:10]So when uh the first description is given that X is found in honey, it is going to be most likely fructose.

[00:02:20]So I think it should be option D.

[00:02:24]Let me check other options also. So other description I mean so keto sugar yes fructose is a keto sugar. Glucose is an aldo sugar exists in alpha and betaic form. Uh I think so it can exist. lio rotator that I don't know but let's see okay so just based on the first option or the first description that it is found in honey I could discern that it is fructose de facto to be specific and all the other things are also important for you to remember maybe they can be asked in some other question but at least knowing the source of sugar in different uh bio polymers or biomolelecules will make your life easier.

[00:03:13]So this was a very easy question plus four marks and you can check the structure here. So it has a keto group that is why it is a keto sugar and the next question is a match the following. So you will see a lot of questions concerning the vitamins section of this chapter that are repeatedly asked. So for example vitamin B12 which is cyanocobalamine when known for causing perinatious anemia when it is deficient. So A should match with four. There are two options like that option B and D. B is matching with three then C which is vitamin B2.

[00:03:55]So B2 I think uh does kiliosis.

[00:04:00]So C should match with one most likely and D is B5.

[00:04:05]B5 with convulsion. I think D should be the correct one. I may be wrong here because I don't remember the functions anymore.

[00:04:13]But at least we can check it. Yes. So it is correct. So B12 is one of the most repeatedly asked. Uh it has a co-actor called cobalt which is a metal. Then its name is cyanocobalamine. All these things are repeatedly asked. Then vegetarian people are also deficient in vitamin B12 because it comes from animal sources and also bacteria. So you might be knowing about supplements vitamin B and C supplements. So B12 is a part of that. What else? Vitamin D is colliferol. So it is important for the bone health. So when vitamin D is deficient that leads to ricketetts which is a condition with uh weak bones. Then vitamin B2 uh I think it leads to the uh breaking of uh tissue around the or the skin around the lips. So that is called kilosis and basics is conversion.

[00:05:14]Let me try to also show what is kiosis.

[00:05:20]inflammatory condition that cause cracking. Yeah. So this is the word I was looking for. Cracking of the corners of the mouth. So just remember this kiliosis.

[00:05:31]You might have seen this is because of deficiency of vitamin B2.

[00:05:37]So cracking of the uh mouth corner of the mouth that is due to the deficiency of vitamin B2.

[00:05:47]I hope it is clear now.

[00:05:50]So let's move on to the next question.

[00:05:52]Very easy question until now down if you know the concepts quite well.

[00:05:57]Next one is from 2024 and here they are asking given below are two statements.

[00:06:02]Glycogen is similar to ami low in its structure and glycogen is found in yeast and fungi also. So glycogen is usually seen in animals. So I think B is in incorrect and glycogen is similar to amos or amopectin.

[00:06:19]So amyo I think is linear. Glycogen is branched. So I think one is also false.

[00:06:27]Let me check. I'm sure that glycogen is branch and also amopectin is branch.

[00:06:32]Amos is unbranched.

[00:06:34]So it should not be similar.

[00:06:38]Oh is it two is true.

[00:06:42]Glycogen is a form of energy storage in many. Okay. It is also seen in other groups. I thought it's the main reserve in animals is glycogen but here it says that it is also seen in plants, bacteria and fungi. Glycogen serves as a reserve of glucose which can be mobilized in. So just remember this also that it is seen in other groups also but this is more important that amyos is a linear polymer. So this can be again asked in some other form and also remember the kind of linkage alpha 14 glycosidic linkage.

[00:07:16]This is the linear chain uh linkage alpha 14. So first carbon and the fourth carbon form the linear chain. But if there is a branching that is alpha 16 linkage.

[00:07:28]So here it's given alpha 16 glyosidic bond at the branching point for branching alpha 16 glyosidic bond and for linear chain formation alpha 14.

[00:07:41]So remember this.

[00:07:44]Next one is the reagents with which glucose does not react to give the corresponding test. So it's basically asking for uh glucose acting as a reducing sugar. So tolerance reagent shifts reagent hydrogen cyanide NH2 and bulfide. So these are the tests and glucose is an aldo sugar if you remember. Fructose is a keto sugar. So which of them will be positive for alihides?

[00:08:17]Actually they're asking does not react.

[00:08:20]So which of them will not react with an alihide?

[00:08:24]Uh this is so I think shifts reagent reacts with alihide. I have to remember this because it's been a long time since I've read this chapter.

[00:08:39]So finite can you guys comment if you know this test I've already explained you the logic band discussion now you just have to remember for which of these reagents does uh the alihides react with or not tolerance reagent is basically I think the silver mirror test so alihides do react with it so a should not be there Then B C B E or B D. So B E BC or E D.

[00:09:17]C is sinide.

[00:09:22]Can site react with adihide.

[00:09:26]So there is H C triple bond N. And here it is C H double bond O maybe HCN and what is the next one?

[00:09:43]N2H NS2 does react. So D is not there.

[00:09:48]So we are left with BC or B uh bulfite. Sodium bulfite.

[00:09:56]Sodium bulfite.

[00:10:03]It's a double bond O double bond O minus.

[00:10:14]I think I will go with uh B and uh B. Let's check B and D.

[00:10:32]I might be wrong. I'm just trying to eliminate the options that do react with alihide and then trying to come up with what will not react.

[00:10:42]Oh, so it's correct.

[00:10:44]Let me see why bulfite I think bulfite is a distinguishing reagent among adiads and ketone as far as I remember. So tolerance reagent is the solution of silver nitrate in ammonia. So this is the classic silver mirror test. Most of us should know this.

[00:11:04]Glucose have a free alihide. It can easily open as he acetyl can reduce the tolerance regent to metallic silver which is the silver mirror formation. So tolerance reagent is positive. Next is sift shifts reagent. So it is again used to detect alihide groups. Alihide group of glucose is present in very minute amount at equilibrium.

[00:11:26]Okay. So leading to negative test. So it requires the free alihid group. However mostly it is cycized the glucose. So then the shift regent can't react with that. Also remember the change in the color. So for free alihides it will turn pink. The solution will turn pink. Next is hydrogen sinide.

[00:11:50]So it will form sino hydrants.

[00:11:54]This is true. In the case of glucose the reactive alihi can react with to form glucosile sinohydrants. So HCN reacts.

[00:12:03]Next is hydroxyamine.

[00:12:06]Again it will form oxy. So all these compounds you should know. So these are coming from the carbonil chapter. If you have studied that then this chapter will find very easy.

[00:12:18]So glucose oxy will be formed. Bulfide reacts with iodide to form bulfide adducts. However, because glucose in solution exists in the cyclic form, it does not easily react with sodium bulfide.

[00:12:32]Glucose generally does not react unless placed in the certain condition. So all the things react with aliite. The thing is because glucose is cycized uh some of them do not react in normal condition as good as the others can.

[00:12:50]So that is why you see that shifts reagent and sodium bulfide will give a negative test.

[00:12:58]So I hope it's clear and let's move on to the next set of questions from ne 2023. So the question is statement one. A unit formed by the attachment of a base to one prime position of sugar is known as nucleotide by the attachment of a base to one prime.

[00:13:18]Okay. When nucleotide is linked to phosphorus acid phosphorus acid five prime position of sugar motive we get nucleotide.

[00:13:29]Phosphoric acid or phosphorus acid. I think second is wrong. A unit formed by the attachment of gl base to the one prime position of sugar is known as nucleotide one prime I think first is correct one is true two is false yes so if you know the structure of these uh DNA RNA bases you will know that the base is linked to the one prime position using an n glycosidic linkage And the phosphate group which is the phosphoric acid will attach to this five prime carbon and then the chain elongation happens via this three prime five prime uh position. So that is why you say that DNA polymerase acts in five prime to three prime direction. RNA polymerase acts so and so.

[00:14:28]So statement is not correct because not linked with phosphorus acid. It's phosphoric acid. Exactly. So there's a difference between this. So phosphorus acid is different. I think it is S3 PO3.

[00:14:41]Phosphoric acid is S3 P4. Depending on phosphorus oxidation state these names are given. So phosphinic acid, phosphorus acid and phosphoric acid.

[00:14:54]Remember these three things.

[00:14:58]You should also know the structure that oxidation states. So it's a droic acid phosphorus acid S3 P3.

[00:15:07]But there are other forms also. So a more oxidized form will be H3P4. A less oxidized form will be H3 P2 which is called phosphinic acid. So just remember these things also.

[00:15:21]Incorrect statement about dennaturation of proteins is uncoiling of the helical structure takes place. Yes, it results due to the change of temperature and pH.

[00:15:30]Yes. Results in loss of biological activity. Yes. Protein is formed from amino acids linked by peptide bonds.

[00:15:42]Protein is formed from amino acids linked by peptide bonds.

[00:15:57]All the statements look correct to me.

[00:15:59]Protein is formed from amino acids linked by peptide bonds. This is true.

[00:16:05]But is it in the context of dennaturation?

[00:16:09]Maybe not. Let's see.

[00:16:12]So proteins are polymers of alpha amino acid. They are connected to each other by peptide one. But this is not dennaturation process. Exactly. So that is why I also became suspicious of this statement because in the context of dennaturation all the other three statements make sense but this one stands out. So maybe they wanted us to find the oddman out among this.

[00:16:37]So next question is from 2022 and it is asking the incur statement regarding enzymes. Enzymes are bio catalyst. Yes, like chemical catalyst. Enzymes reduce the activation energy of boprocess.

[00:16:50]True. Enzymes are polyaccharides. No, mostly they are protein, but they can also be RNA like ribosyme.

[00:16:59]Enzymes are very specific for a particular reaction substrate. This is also true. There may be some uh degree of non-specificity but most of them are very very specific.

[00:17:10]So in that sense, fourth is also correct. Three is obviously wrong. Which is the basic amino acid? This is a very basic question. So basic amino acid all of us know it's lysine, histadine and arginine. So these three basic amino acids you should know. Then acidic amino acid, aspartic acid and glutamic acid.

[00:17:34]And uh when you are asked about u aromatic amino acid then you should remember uh tryptophan, tyrosine, phenile alanine. Then there are uncharged charged all these amino acids you should know. Uh O containing ones are serene and tyrosine also has O which is phenolic O and threeonine also has O.

[00:18:01]Then sulfur containing there is cysteine and methionine. So methionine has S CH3.

[00:18:08]Cyine has SH which can form dulfide linkages to form the cyine form which has SS sulfital group uh which is basically cross link. So that is also giving some kind of secondary structure to the proteins. So I basically divide revised all the amino acids for you in this question.

[00:18:31]Next is sucrose on hydraysis. So basically it's asking what are the components of sucrose. So alpha dlucose and beta d fructose. I think this one should be correct. Yes, very easy question non-essential. So you can see the questions are very easy. If you just know the theory quite well, you can easily solve it. You don't have to know a lot of things here.

[00:18:59]Next one is the non-essential amino acids. So there is a pneummonic for this. I have made a pneummonic while preparing for the exam and I also shared it on my channel. So how I remember it is illp.

[00:19:15]So isolation leucin lysine then methionine proline mp thenine alanine then tryptophan then valin and histadine these are the essential amino acids. So isolation lucin valin is there uh l m then t a t v h isolution le oh no le is not there isolution le is also there isolation leen proline in some cases uh like in the NCT I remember there are 10 amino essential amino acids in some places they have eight or something like that some are semi- essential so MP oh I think it's Arj not name So alen is in is non- essential.

[00:20:34]Yeah. So t a t. So that a is argin. You also have to remember which a is that.

[00:20:40]Uh otherwise it's a very straightforward question. If you remember the pneummonic you can do it within 10 seconds actually.

[00:20:47]Following compounds can form a zutter ion. So it's basically asking you about amino acids which are zutter ionic species. So they can form this plus and minus dipole-like structure. That is why it is called zwitter ion. Zit z meaning two in German. So that is why this can form a zutter ion.

[00:21:09]Difference between amyos and amilopectin. See that uh the glycogen question concept is repeated here directly. Amilopectin has 14 linkage and 16 linkage. True. Amos has 14 and 16. No amilopectin have 14 alpha 16 beta.

[00:21:31]Uh yeah I think this one is more correct. Branching is 16 beta.

[00:21:37]Oh no 16 alpha.

[00:21:41]Oh because this is dlucose. Okay. Okay.

[00:21:44]So both are alpha linkages but the straight chain is 14 but the branching is 1 six. Just remember this.

[00:21:52]Next one is so we have already gone past a decade. We are in 2017 now is not correct. Oalin is a simple food reserve in egg white could be blood proteins from fiber gener blood clotting. Yes.

[00:22:07]Did they actually make the protein more active? No. This is definitely incorrect. Insulin maintains the sugar level in the blood. Yes.

[00:22:15]Next one is name of the four aldos with configuration given below.

[00:22:21]So L L and D if we can assign the configuration L or D then the names will be easier. So this is from 2016 10 years ago.

[00:22:37]I don't remember the name of this sugar based on the position of O and H and I don't think they will ask these kind of questions anymore.

[00:22:49]So first one is all are in the same configuration a lot configuration I mean the same projection which is on the same side and first one and third one first one is likely D third one is likely L now whether it is or fuse Trios I think is on opposite side. So this is likely arythros.

[00:23:26]So I will go with option D.

[00:23:30]First one is likely D ariththros and second one is D3OS.

[00:23:38]Yes it is correct. So sometimes you have to remember the pneumonics or remember how the structure looks like.

[00:23:46]So I remember that 3O has a O on the opposite side. So that is why I could eliminate two options and then whether it is D or L I could see based on the position of O. Although that is not always true but in this case uh this is how I remember that if O is on the right side it is D rotatory and uh like dextrot and if O is on the left side it is lio rotatory.

[00:24:12]But it can be different also depending on the molecule. But here it work like for simple sugars it works sometimes.

[00:24:21]So the central dogma of molecular genetics basically is saying DNA to RNA, RNA to protein.

[00:24:28]Super easy questions.

[00:24:31]Correct statement regarding RNA and DNA.

[00:24:33]Sugar component in RNA is an arinos and the sugar component in DNA is ribos. No DNA is also ribos. RNA is also ribos.

[00:24:43]The difference is DNA has deoxyibbos because the two prime O gets converted to just H.

[00:24:52]So first one is incorrect. Sugar component in RNA two prime deoxyos. No.

[00:24:58]Sugar component in RNA is arabinos. No, only the fourth one is correct.

[00:25:05]Again very easy question. Protein molecule various amino acids are linked together by peptide bond.

[00:25:13]Even a beginner can answer this. Whoever has started uh reading the biomolelecule chapter, they can easily answer such questions. Next one is asking. So now we have reached AIPMT level.

[00:25:27]D plus glucose reacts with hydroxyamine and yields an oxy. The structure of the oxy would be so glucose has an O alihide not O C double bond O H. So if it reacts with hydroxyamine which is NH2 similar to the question that was asked later on regarding which of these can react with the glucose.

[00:25:53]So H2 will be gone from here and I think first one looks okay to me.

[00:26:00]Next one is also fine but what is the difference? D plus glucose. Okay. So first we have to think about which of them is D plus glucose.

[00:26:11]For that you have to remember the structure of D plus glucose.

[00:26:15]So I think the O on the second last carbon should be on the right side and before that it should be left.

[00:26:28]First one looks correct to me. I may be wrong because I don't remember the structure of D plus glucose now.

[00:26:36]Yeah, it's wrong. So it's the D1.

[00:26:39]Okay. So most of the O are on the right side. Only one O is on the left side.

[00:26:44]Okay. Now I think this is how it should be. But anyway, you can remember the structure of D plus glucose. Just remember that all the O should be on the right side for the deconfiguration except for the third carbon.

[00:27:03]Next question is hormone is produced under the condition of stretch stress stress adrenaline again very easy question DNA linkage between different nitrogenous base. So this is different nitrogenous bases linkage between different nitrogenous base hydrogen bonding. Yeah, two nitrogen uh bonds. Two nitrogen base uh are basically interacting via the hydrogen bonding. So there is no bond as such. These are just u you can say charge interactions.

[00:27:49]Vitamin B1 B1 I think deficiency causes berry berry very easy to remember B1 berry berry it's one of the easiest to remember sets of monossaccharides form sucrossse again a similar question was asked so this is repeated alpha dl glucopyronos and beta d fructo furanos very easy questions dennaturation again as Question related to dennaturation protein causes loss of secondary and tertiary structure. Yes. Lefts to the conversion of double strand of DND into single strand. I think it should be DNA.

[00:28:29]That is some typo.

[00:28:31]Uh yes, dennaturation affects primary structure which gets distorted.

[00:28:37]No, primary structure is not affected.

[00:28:39]So one and two are correct.

[00:28:45]not a fat soluble vitamin. So vitamin B and C are water soluble others are fat soluble.

[00:28:52]So very easy again is not true regarding plus lactose. What is plus lactose? I think D plus lactose again that is a typo. On hydraysis lactose gives equal amount of glucose and galactose.

[00:29:08]glucose and galactose. I think this is correct.

[00:29:12]It's a beta gluccoside formed by the end of glucose and molecule of galactose.

[00:29:19]Not true. It is asking what is not true.

[00:29:22]Lactose is a reducing sugar and does not exhibit mutation.

[00:29:27]C 12 H21 contains A2 groups. Lactose is a reducing sugar. No, I think this one is false. Others are true.

[00:29:41]So fructose is so the explanation here is lactose is a reducing sugar and shows neutral rotation. Fructose reduces to tolerance region due to so in fructose solid by convergent to alihide by base. Yes.

[00:30:00]So the inol forms and then there is this uh alihide formation which is the main functional group that reacts with the tolerance region to reduce the AgNO3 in ammonia to um silver metal does not exhibit the phenomenon of neutarotation does not exhibit I think it should be sucrossse.

[00:30:27]Yes, only those sugar which have free alihide or ketone can show. So sucrose you know the structure the glucose and fructose are linked and it does not have any free alihide or ketone to show the mutation and it is also non-reducing.

[00:30:46]The segment of DNA which acts as the instrumental manual for the synthesis of protein is nucleotide.

[00:30:54]Now segment of DNA acts as the instrument for synthesis of protein gene.

[00:31:00]That segment is called as structural gene or coding sequence you can say more appropriately.

[00:31:07]Hormone containing iodine again very easy it is thyroxine T3 and T4. You should know the structure of T3 and T4 also. So here the structure is also given. So it's modified uh form of tyrosin. You can see this part is looking like tyrrosin and then actually this part and then you have addition of iodine. So there are pumps that import the iodine and then so I think it is called vendrin or something which is pres present in the thyroid gland. So there is a step by pro step wise process to make this. You should also read that if you have time otherwise you can just read whatever is given in NCERTT. The effect of thyroxine which is the active form which is the inactive form so on and so forth. What are the different conditions when there is higher level of uh thyroxine like increase in the bal basal metabolic rate and so on which is an amine hormone amine.

[00:32:11]So it should be I think thyroxine.

[00:32:15]Yes. because it has this amino group and also it is formed from the amino acid uh tyrosine.

[00:32:22]As I explained a few moments ago, the DNA complimentary bases are AT and CG. AT and CG.

[00:32:35]You can see the questions are very very easy. Vitamin A is water soluble again same question. So B and C are water soluble.

[00:32:44]DNA and RNA are kyal molecules. Their kyality is due to kyal phosphate estester unit. No kyal bases d sugar component l sugar component.

[00:33:03]DNA and RNA are kyal. Why are they kyal?

[00:33:07]Bases are kyal.

[00:33:13]I think so bases are Kyle. No, but bases do they have chyal carbon?

[00:33:18]No. It is because of the sugar and the sugar is dugar. Yes. If you look at the structure of the bases, they are mostly double bonded. So it's an aromatic ring.

[00:33:31]So you don't have a kyal center as such.

[00:33:34]Phosphate again you don't have a kyal center. But in the sugar you have single bonded carbon and there are some chyal carbons because of the presence of O H and the other groups making the molecule optically active. So the kyality is due to the sugar and dugar in case of DNA RNA.

[00:33:58]Next question is asking proteins to polyeptide and then polyeptide to amino acid. So protein to polyeptide will be pepsin and yes this happens in pepsin acts in the stomach and then goes in the uh I think diodenma or small intestine somewhere between the diodenma and small intestine.

[00:34:23]So that is released by the pancreatic duct also. Human body does not produce vitamins peptide hormone. Peptide peptide hormone is thyroxine is an amino hormone. I showed you a few moments back. Testosterone is a steroid hormone. You know the structure of cholesterol. So from that testosterone is formed. Then glucagon and insulin are peptide hormone and adrenaline is adrenaline is again I think maybe not a peptide hormone. Let me check the structure of adrenaline.

[00:35:54]For some reason the first letter is not getting typed. So adrenaline is like this.

[00:36:01]Okay. This is also having an amino group.

[00:36:08]But this is a secondary amino.

[00:36:14]Maybe it's a modified amino group but it's not a peptide for sure. So glucagon insulin all these are peptide hormone and you should also know the structure of insulin how many amino acid it has 51 amino acid. I think there are three chains chain A, B and C. C is removed from the pro-inssulin to form the mature insulin. You should also know the dulfide linkages between which uh amino acids all that thing and if it is possible you should also remember the position between uh the two sulfural bridges but that is at an advanced level. First you should focus on the things that are given in NCERTT. The cell membranes are mainly composed of phospholipid participate in dulfide. So we were talking about dulfide it is thol SH.

[00:37:09]Next is peptide chain. So peptide chain will have C double bond O NH C double bond O N H B is not correct. C double bond to NH C bond to NH C bond this looks correct. C double bond to NH C1 bond to NH C looks correct to me.

[00:37:35]Yes, Cbond to NH is the peptide linkage. Very easy. So now we have gone around two decades back in history. So we are reaching 2004.

[00:37:48]A sequence of how many nucleotides in messenger are in triplet triplet where is three?

[00:37:55]So codon triplet very easy and correct statement in respect to hemoglobin catalyst for biological reaction no maintain blood sugar level no that is insulin oxygen carrier yes structure of protein is stabilized by hydrogen bond should also know the position of hydrogen bond. So in alpha helix there is hydrogen bonding between the i amino acid and i + 4th amino acid. So based on that you can also calculate how many hydrogen bonds will be there. And there are different kinds of alpha helysis like 3.6 alpha 13 helix. Then there is pi helix.

[00:38:40]There is 310 alpha helix. But that will study at a higher stage. For now you can just focus on alpha helix and beta sheet. In the primary things the hormone that helps in the conversion of glucose to glycogen is glucose to glycogen. So it should be I think insulin.

[00:39:02]Okay. So I think we have practiced a lot of questions today and let me check how much time it's already 40 minutes. So I will stop the stream here. If you are new on this channel, feel free to subscribe to this and also share it with your friends and do like this video and share it with your friends as I said so that they can also take part and uh understand how to solve the questions in a quick way with the concepts. So with that I will end this session and I hope to study well and keep do and uh keep well. Okay. So, keep studing and doing hard work. Bye-bye.