COMEDK Chemistry PYQs (Last 10 Years) | Biomolecules Chapter with Solutions

Added: 2026-05-12

[00:00:00]Hello champions, welcome to the channel and in today's video we are going to solve the last 10 years of COMEDK PYQs of a very easy chapter that is biomolecules. Now before starting let's understand the weightage of this chapter. So if you analyze for last 3 years, in 2023 the number of questions asked were four and in 2024 the number of questions asked were four but in 2025 the number of questions asked were three, okay? So three to four questions you can easily expect from this chapter.

[00:00:26]So please prepare this chapter thoroughly because it is a very easy fact based questions, no more reactions to remember. So please go through on the last two days also if you just see my one shot video on this chapter you will be able to solve all the questions, okay? So let's get started with our first question. This is very simple question here. Which set is the correct pairing set responsible for the structure of DNA? So you know that pairing happens between AT and GC, okay? So that is there in option number A, so option number A is the correct answer. Next, the structural feature that distinguishes proline from all other amino acids are. So proline is a secondary amine, so option number A, all other are primary.

[00:01:05]Next we have when glucose reacts with bromine water the main product is. So remember here in the identification of structure of glucose there are five reactions. The first one is the reaction with HI. The second one is the reaction with NH2OH and HCN. The third one is the reaction with bromine water. The fourth one is the reaction with acetic anhydride. And the fifth one is I think the reaction where with nitric acid, okay? Now these five reactions tells us what conclusion we got and based on this conclusion the structure of glucose was determined. So you need to remember all these five reactions. What are the reagents used? What is the product formed and from that product what conclusion was derived? That is most important part, okay? Now if you see with bromine water it gave you gluconic acid, so option number B here. Before moving ahead, so students if you have appeared for KCET examination and now if you want to know what would be your expected rank in KCET 2026 then me and my team has done a lot of research and prepared the special tool for all of you which link is there in the description section. So if you click on the link and sign in you will come to this page and this page you have to enter your PCM marks and you have to enter your KCET score and then just click on predict rank and you will get your estimated rank, okay? Now please don't compare it with the 2025 data because we know in 2025 the paper was very easy and the cut off was very high but same is not the scenario in 2026, okay? So that definitely the cut off will go down. So please just check here and you can also see an expected rank range as well. And not only that, if you scroll up you can see you can select the branches in which you are interested in and you can see what all colleges are there that is suitable for your rank and this will definitely help you in your counseling and just to understand what all options are available for you, okay? So please do check this out. The link is there in the description section.

[00:02:55]Moving ahead to the question number four here.

[00:02:58]The sequence in which the amino acids are arranged in a protein is called as your primary structure. Now let's see question number five here. Which of the following structures for the nucleotide is not correct? So in a nucleotide what you have? You have a sugar group, right?

[00:03:11]On one side you have the nitrogenous base and on the other side you have the phosphate group, okay? Now if you see in this cytosine ribose phosphate this is correct. Uracil 2-deoxyribose and phosphate. Now here if you see 2-deoxyribose is present in DNA and uracil is not present in DNA. So this is not a correct match. So option number B here. Next, pick up the incorrect statement from the following. Glucose exists in two different crystalline forms, alpha and beta. That is a correct statement. Cyclic structure of alpha D and beta D glucose are called pyranose.

[00:03:41]That is also correct. Alpha D and beta D are enantiomers. This is incorrect because they are anomers. So option number C here. Which of the following is an acidic amino acid? Glutamic acid is an acidic amino acid because we have two COOH group in the compound. Study [snorts] the structure of maltose and mark the incorrect statement. Maltose is composed of two alpha D glucose units, correct. C1 of one end is connected with the C4 of other, correct. It is a non-reducing sugar. No, it is a reducing sugar. So option number C here. In DNA the complementary bases are um AT and GC, okay? So option number B here.

[00:04:16]Next, RNA is different from DNA because RNA contains Okay, uh ribose and thymine? No. Ribose and uracil. It is thymine is present in DNA as well but uracil is present only in RNA. Next, in nucleic acids the sequence is nucleic acids the sequence is sugar base phosphate, base sugar phosphate, base phosphate sugar, none of these. So the order is actually you have sugar at the middle, okay? And on the both side you have base and phosphate. Sugar is always at the middle. Here these all options are incorrect. Option number B is correct answer. Next, in cellulose the D glucose units are joined by beta 1-4 glycosidic linkage. Next, glucose reacts with acetyl chloride to form pentaacetyl glucose. It indicates the presence of. So this I was talking about. You should know all the five reactions, the products and the conclusion that it gives you. So five when pentaacetyl glucose is formed it concludes that there are five OH groups.

[00:05:15]Next, in sucrose the glycosidic linkage is between one and two, so option number D here. What is the basic formula of starch? So starch is formed after the removal of water from glucose molecule.

[00:05:25]So we have C6H12O6, okay? Now if you remove water molecule here it will become C6H10O5, okay? So it is that one, option number B here. Next, the protein responsible for blood clotting is fibrinogen, option number D here. Which of the following is not a steroid hormone?

[00:05:45]Oxytocin is not a steroid hormone. All others are your steroid hormones. Which among the following proteins is a transporting agent? So hemoglobin, we all know it transports oxygen and carbon dioxide in the human body. A non-reducing sugar found in the honey is So first of all, non-reducing it is asked and all of these are actually reducing sugar. So from easily you can eliminate this option and the correct answer will be D here. Next, to which category of compounds the immunoglobulins belong? You can see from the word immuno is there, okay? So these belongs to antibodies. Next, ninhydrin test is used for the identification of amino acids. Next, thymine is actually five methyl uracil. So for all the four bases you should know their structure actually, what is the difference in between them. Next, alpha containing amino acid is cysteine. Which of the following ions can cause the coagulation of protein? Calcium. Next, uh Next we have uh biuret test is answered by proteins.

[00:06:42]Indigestible carbohydrate which is not a constituent of our which is also a constituent of our diet is your cellulose. We eat plants and the plant cell walls are made up of cellulose. So it is a part of our diet. Next, the sequence of bases on RNA molecule synthesized on the GCAT is strand of DNA, okay? So GC, CG, A will be T but in place of T in RNA you will have U. And then T will be again A, A will be T but in RNA we will have Sorry, in RNA we will have U here. So CGUA U, option number A here. Next, alpha helix and beta pleated are your secondary structures. Fibrous and globular are your tertiary structures, okay? And primary structure is just the sequence of amino acids.

[00:07:26]Next, which statement is not true for describing enzymes? They are polypeptides. They are glycosidic linkage. No. If they are polypeptides they cannot have glycosidic linkages because this is present in um carbohydrates or in the sugars, okay? So or in the saccharides. So if they are polypeptides there will be amide linkages between the different amino acids. Next, which of the following are monosaccharides, okay?

[00:07:49]So if you see glucose and ribose are monosaccharide because here maltose and sucrose are your disaccharides. Next, in nucleic acids the nucleotides are linked by phosphodiester linkage or only ester linkage. Amino acids exist as zwitterion at isoelectric pH. In DNA the linkages between different nitrogenous bases are hydrogen bonding where we have AT and GC.

[00:08:13]Next, which one of the following is not a protein? Cellulose is a carbohydrate or it's not a protein. Proteins can be hydrolyzed by using uh here you can see acids can work, alkalis can work, enzymes can work, so all of the above.

[00:08:27]Next, a nucleoside on hydrolysis gives you. So if you remember in a DNA should see DNA is made up of what? Nucleotides.

[00:08:36]Okay. Next, nucleotides when they are connected to each other by phosphodiester linkage we get DNA. Now nucleotides consist of like this, nucleoside plus phosphate group. Now nucleoside contains sugar plus nitrogenous base.

[00:08:56]Okay. So a heterocyclic base and a orthophosphoric acid. No, it contains a sugar and a base. An aldose pentose, a heterocyclic base and orthophosphoric acid. No, orthophosphoric acid is not included here. A pentose sugar and a heterocyclic base. Yes, this constitutes of nucleoside. Now when you add phosphate group to this it becomes nucleotide and when the nucleotides combine with each other you get nucleic acids, okay? Next, which one of the following does not correctly match with each other, okay? Silk is a polyamide, lipase is an enzyme, butter is a fat, oxytocin is not an enzyme, it is a hormone. So option number D here, okay?

[00:09:33]So students, that's all in the last 10 years of COMEDK PYQs for biomolecules, very easy chapter. Just revise all the students for example all the disaccharides, what are the linkages in polysaccharides, what are the linkages? Just go through this and the deficiency disease that vitamin deficiency table and the hormones part, revise it thoroughly, okay? That's all in this video and just stay tuned for the next chapter and the link of the predictor is there in the description section. Do check it out to see your rank in KCET 2026, okay? All the best.