Biomolecules NEET PYQReal NEET & AIPMT 2005–2021 questions, year-tagged, with solutions
By the RankUp team, founded by Dr. Deepak Sahu (MBBS Gold Medalist, NEET PG AIR 1731) · Updated
Every Biomolecules question from the NEET & AIPMT papers on this site (2005–2021), newest first. Each is tagged with its paper. Tap an option to check your answer and read the explanation.
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Biomolecules previous year questions
32 questions. Tap an option to check your answer.
Q1NEET 2021
The RBC deficiency is deficiency disease of :
Not quite — the answer is A.
Vitamin B₁₂ is needed for red blood cell formation; its deficiency causes pernicious anaemia. Vitamin B₁ deficiency causes beriberi and B₂ deficiency causes cheilosis, not an RBC deficiency.
Q2NEET 2020 · Q117
Which of the following is a basic amino acid ?
Not quite — the answer is D.
Lysine has an extra –NH₂ group on its side chain, so it has more amino groups than carboxyl groups and is basic. Serine, alanine and tyrosine have neutral side chains.
Q3NEET 2020 · Q121
Sucrose on hydrolysis gives :
Not quite — the answer is C.
Sucrose is formed by a glycosidic link between C1 of α-D-glucose and C2 of β-D-fructose, so hydrolysis releases α-D-glucose and β-D-fructose. Swapping the anomers (β-glucose, α-fructose) is the usual trap.
Q4NEET 2019 · Q64
The non-essential amino acid among the following is:
Not quite — the answer is C.
Alanine can be synthesised in the body, so it is non-essential. Valine, leucine and lysine must be obtained from the diet and are essential amino acids.
Q5NEET 2018 · Q53
Which of the following compounds can form a zwitterion?
Not quite — the answer is D.
Glycine has both an acidic –COOH and a basic –NH₂ group, so an internal proton transfer gives H₃N⁺–CH₂–COO⁻. Benzoic acid and aniline have only one of these groups, and the N in acetanilide is not basic.
Q6NEET 2018 · Q56
The difference between amylose and amylopectin is
Not quite — the answer is C.
Amylose is an unbranched chain of α-D-glucose with C1→C4 α-glycosidic links. Amylopectin is branched: C1→C4 α-links in the chain and C1→C6 α-links at branch points. Starch has no β-links, and amylose contains only glucose.
Q7NEET 2017 · Q32
Which of the following statements is not correct?
Not quite — the answer is D.
Denaturation destroys the secondary and tertiary structure of a protein, so it loses its biological activity rather than gaining it. The other statements are correct: insulin regulates blood glucose, ovalbumin is the storage protein of egg white, and thrombin and fibrinogen take part in clotting.
Q8NEET 2017 (Gujarati paper) · Q34
The letter 'D' in D-glucose signifies:
Not quite — the answer is D.
'D' refers to the relative configuration of the lowest (penultimate) chiral carbon, C-5 in glucose, which matches D-glyceraldehyde (–OH on the right). It says nothing about the sign of rotation; that is shown by (+) or (−), and D-fructose, for example, is laevorotatory.
Q9NEET 2017 (Gujarati paper) · Q43
Which of the following amino acid is not optically active?
Not quite — the answer is D.
Glycine, H₂N–CH₂–COOH, has two hydrogens on its α-carbon, so it has no chiral centre and is optically inactive. Proline, serine and leucine all have an α-carbon with four different groups.
Q10NEET 2016 Phase 2 · Q82
The central dogma of molecular genetics states that the genetic information flows from
Not quite — the answer is C.
Genetic information is copied from DNA into messenger RNA (transcription) and then read to make proteins (translation). Carbohydrates are not products of genetic information transfer, and information does not flow from proteins back to DNA.
Q11NEET 2016 Phase 1 · Q56
In a protein molecule various amino acids are linked together by:
Not quite — the answer is C.
Amino acids join through the –CO–NH– amide linkage formed between the carboxyl group of one and the amino group of the next; this is the peptide bond. Glycosidic bonds link monosaccharides in carbohydrates, not amino acids.
Q12NEET 2016 Phase 1 · Q87
The correct statement regarding RNA and DNA, respectively is:
Not quite — the answer is B.
RNA contains β-D-ribose, while DNA contains β-D-2-deoxyribose, which lacks the oxygen at C-2'. Arabinose is not a nucleic acid sugar.
Q13NEET 2016 Phase 1 · Q89
Which one given below is a non-reducing sugar?
Not quite — the answer is D.
In sucrose the glycosidic link joins C1 of glucose to C2 of fructose, so both anomeric carbons are tied up and there is no free hemiacetal group to reduce Tollens' or Fehling's reagent. Maltose and lactose keep one free anomeric carbon, and glucose is a free aldose, so all three are reducing sugars.
Q14AIPMT 2014
Which of the following hormones is produced under the condition of stress which stimulates glycogenolysis in the liver of human beings?
Not quite — the answer is B.
Adrenaline (epinephrine), the 'fight or flight' hormone, is released under stress and promotes glycogenolysis in the liver to raise blood glucose. Insulin does the opposite, favouring glycogen formation.
Q15AIPMT 2014
D(+) glucose reacts with hydroxyl amine and yields an oxime. The structure of the oxime would be: (Fischer projections: C-1 is CH=NOH and C-6 is CH₂OH; the side of the –OH group on C-2, C-3, C-4 and C-5 is given)
Not quite — the answer is C.
Oxime formation only changes the C-1 aldehyde to CH=NOH, so the D-glucose configuration is retained: –OH on the right at C-2, left at C-3, and right at C-4 and C-5.
Q16AIPMT 2012 Prelims
Deficiency of vitamin B₁ causes the disease
Not quite — the answer is C.
Thiamine (vitamin B₁) deficiency causes beri-beri. Cheilosis is caused by riboflavin (B₂) deficiency, convulsions by pyridoxine (B₆) deficiency and sterility by vitamin E deficiency.
Q17AIPMT 2012 Prelims
Which one of the following statements is incorrect about enzyme catalysis?
Not quite — the answer is A.
Enzymes show maximum (not least) activity at their optimum temperature, so that statement is incorrect. The other statements are true: most enzymes are proteins, their action is highly specific, and heat or UV radiation denatures them.
Q18AIPMT 2012 Prelims
Which one of the following sets of monosaccharides forms sucrose?
Not quite — the answer is C.
Sucrose is formed by a glycosidic link between C1 of α-D-glucopyranose and C2 of β-D-fructofuranose. Fructose occurs as the five-membered furanose ring in sucrose, not as fructopyranose, and galactose is a component of lactose.
Q19AIPMT 2011 Mains
Which of the statements about "Denaturation" given below are correct? (a) Denaturation of proteins causes loss of secondary and tertiary structures of the protein (b) Denaturation leads to the conversion of double strand of DNA into single strand (c) Denaturation affects primary structure which gets distorted
Not quite — the answer is A.
Denaturation disrupts the secondary and tertiary structure of a protein, and in DNA it separates the double helix into single strands. Peptide bonds are not broken, so the primary structure is unchanged; any combination including that statement is wrong.
Q20AIPMT 2011 Mains
Which of the following is not a fat soluble vitamin?
Not quite — the answer is C.
Vitamins A, D, E and K are fat soluble, while the B-complex vitamins and vitamin C are water soluble. So vitamin B complex is not fat soluble.
Q21AIPMT 2011 Prelims
Which one of the following statements is not true regarding (+) Lactose?
Not quite — the answer is D.
Lactose has a free hemiacetal group on its glucose unit, so it is a reducing sugar and does show mutarotation; the statement that it does not mutarotate is false. It has 8 –OH groups, is a β-glycoside of D-galactose and D-glucose, and hydrolyses to equal amounts of the two.
Q22AIPMT 2010 Mains · Q119
Fructose reduces Tollens' reagent due to
Not quite — the answer is D.
Fructose is a ketose, but in alkaline Tollens' reagent it undergoes enolisation (via an enediol) and isomerises to aldoses, which are then oxidised. The alcoholic groups or asymmetric carbons do not reduce Tollens' reagent.
Q23AIPMT 2010 Prelims · Q87
Which one of the following does not exhibit the phenomenon of mutarotation?
Not quite — the answer is B.
Mutarotation needs a free hemiacetal/hemiketal group that can open and re-close. In sucrose the anomeric carbons of glucose and fructose are joined in the glycosidic bond, so sucrose is non-reducing and shows no mutarotation. Fructose, lactose and maltose have a free anomeric carbon.
Q24AIPMT 2009 Prelims · Q167
The segment of DNA which acts as the instrumental manual for the synthesis of the protein is:
Not quite — the answer is B.
A gene is the segment of DNA that carries the coded information for making a particular protein. Ribose is a sugar, and nucleosides and nucleotides are only the building units of nucleic acids.
Q25AIPMT 2009 Prelims · Q200
Which of the following hormones contains iodine?
Not quite — the answer is C.
Thyroxine, secreted by the thyroid gland, is an iodinated derivative of tyrosine. Testosterone is a steroid, adrenaline a catecholamine and insulin a polypeptide; none contain iodine.
Q26AIPMT 2008 Prelims · Q93
In DNA, the complementary bases are
Not quite — the answer is B.
In DNA, adenine pairs with thymine (two hydrogen bonds) and guanine pairs with cytosine (three hydrogen bonds). Uracil occurs in RNA, not DNA, and adenine with guanine would pair two purines, which does not fit the helix.
Q27AIPMT 2008 Prelims · Q100
Which one of the following is an amine hormone?
Not quite — the answer is B.
Thyroxine is made from the amino acid tyrosine and is classed as an amino acid-derived (amine) hormone. Progesterone is a steroid hormone, insulin is a polypeptide, and oxypurin is a purine derivative, not a hormone.
Q28AIPMT 2007 Prelims · Q52
RNA and DNA are chiral molecules, their chirality is due to
Not quite — the answer is C.
The bases and phosphate groups are achiral; the chirality of DNA and RNA comes from the D-ribose/D-deoxyribose sugars. Natural nucleic acids contain D-, not L-, sugars.
Q29AIPMT 2007 Prelims · Q71
Which of the following is water-soluble?
Not quite — the answer is D.
B-group vitamins (and vitamin C) are water-soluble. Vitamins A, D, E and K are fat-soluble and stored in the liver and adipose tissue.
Q30AIPMT 2006 Prelims · Q57
The human body does not produce :
Not quite — the answer is B.
The human body synthesises its own DNA, hormones and enzymes, but most vitamins cannot be made in adequate amounts and must come from the diet. That is why vitamins are called essential dietary factors.
Q31AIPMT 2006 Prelims · Q72
Which one of the following is a peptide hormone ?
Not quite — the answer is A.
Glucagon is a peptide hormone of 29 amino acids made by pancreatic α-cells. Testosterone is a steroid, while thyroxine and adrenaline are derived from the amino acid tyrosine and are not peptides.
Q32AIPMT 2005 Prelims · Q86
Which functional group participates in disulphide bond formation in proteins ?
Not quite — the answer is B.
Disulphide bridges (–S–S–) form by oxidation of the thiol (–SH) groups of two cysteine residues. Thioethers (as in methionine) and thioesters do not form disulphide bonds.
How often Biomolecules came up
Questions from this chapter in each paper on this site.
- NEET 2021: 1
- NEET 2020: 2
- NEET 2019: 1
- NEET 2018: 2
- NEET 2017: 1
- NEET 2017 (Gujarati paper): 2
- NEET 2016 Phase 2: 1
- NEET 2016 Phase 1: 3
- AIPMT 2014: 2
- AIPMT 2012 Prelims: 3
- AIPMT 2011 Mains: 2
- AIPMT 2011 Prelims: 1
- AIPMT 2010 Mains: 1
- AIPMT 2010 Prelims: 1
- AIPMT 2009 Prelims: 2
- AIPMT 2008 Prelims: 2
- AIPMT 2007 Prelims: 2
- AIPMT 2006 Prelims: 2
- AIPMT 2005 Prelims: 1
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