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Class 11 MCQ Questions of Biomolecules with Answers

CBSE Class 11 Biology MCQ Questions of Biomolecules with Answers available in free. The MCQ Questions for Class 11 Biology with answers have been prepared as per the latest 2021 syllabus, and examination pattern suggested in Standard 11 by CBSE. Multiple Choice Questions for important part of exams for Class 11 Biology and if practiced properly can help you to get higher marks.

Biomolecules are the most essential organic molecules, which are involved in the maintenance and metabolic processes of living organisms. These non-living molecules are the actual foot-soldiers of the battle of sustenance of life. They range from small molecules such as primary and secondary metabolites and hormones to large macromolecules like proteins, nucleic acids, carbohydrates, lipids etc.

Explore numerous class 11 MCQ Questions of Biomolecules with answers will help the students analyse their level of preparations and understand the concept well of this chapter.

Practice MCQ Questions for class 11 Biology

1. Feedback inhibition of enzymes is affected by which of the following

(a) enzyme
(b) substrate
(c) end products
(d) intermediate end products

2. Enzymes increase the rate of reaction by

(a) lowering activation energy
(b) increasing activation energy
(c) increasing temperature and pH
(d) decreasing temperature and pH

3. Assertion: Arachidic acid is an unsaturated fatty acid.
Reason: There are one or more double bonds between carbon atoms in unsaturated fatty acids

(a) Both Assertion and Reason are true and Reason is the correct explanation of the Assertion.
(b) Both Assertion and Reason are true but the Reason is not the correct explanation of Assertion.
(c) Assertion is true, but Reason is false.
(d) Both Assertion and Reason are false

4. A protein having both structural and enzymatic traits is

(a) Collagen
(b) Trypsin
(c) Myosin
(d) Actin

5. The fastest enzyme known is

(a) DNA polymerase
(b) carbonic anhydrase
(c) carbonic dehydrogenase
(d) DNA ligase

6. Ester linkages occur in

(a) Proteins
(b) Lipids
(c) Nucleic acids
(d) Carbohydrates

7. The naturally occurring form of amino acid in proteins

(a) L-amino acids only
(b) D-amino acids only
(c) Both L and D amino acids
(d) None of these

8. The most common monomer of carbohydrates is

(a) Sucrose
(b) Fructose
(c) Maltose
(d) Glucose

9. Which one is a fibrous protein?

(a) Collagen
(b) Haemoglobin
(c) Globulin
(d) Hordein

10. Metabolic intermediates found in the living system which are essential for growth and life is called……..
(a) Saponins
(b) Tannins
(c) Secondary metabolite
(d) Primary metabolites

11. Carrier ions like \(Na^+\) facilitate the absorption of substances like:

(a) amino acids and glucose
(b) glucose and fatty acids
(c) fatty acids and glycerol
(d) fructose and some amino acids

12. The helical structure of protein is stabilized by

(a) Hydrogen bonds
(b) Disulphide bonds
(c) Peptide bonds
(d) None of these

13. Enzymes that catalyse the removal of groups from substrates by mechanisms other than hydrolysis, and addition of groups to double bonds, are called

(a) lyases
(b) dehydrogenases
(c) Both
(d) None of these

14. A segment of DNA has 120 adenine and 120 cytosine bases. The total number of nucleotides present in the segment is 

(a) 120
(b) 240
(c) 60
(d) 480

15. Enzymes having slightly different molecular structures but performing identical activity are 

(a) holoenzymes
(b) isoenzymes
(c) apoenzymes
(d) coenzymes

16. In RNA, thymine is replaced by 

(a) adenine
(b) guanine
(c) cytosine
(d) uracil

17. Which one contains four pyrimidine bases?


18. Which biomolecule is distributed more widely in a cell?

(a) Chloroplast
(b) RNA
(c) DNA
(d) Spaherosomes

19. Most abundant RNA in the cell

(a) rRNA
(b) mRNA
(c) tRNA
(d) tRNA threonine

20. Name the simplest amino acid

(a) Alanine
(b) Tyrosine
(c) Asparagine
(d) Glycine

21. The most common secondary structure of proteins is

(a)  βpleated sheet
(b)  βpleated sheet parallel
(c) βpleated sheet non-parallel
(d)  αhelix

22. In which of the following an anticodon occurs

(a) tRNA
(b) mRNA
(c) rRNA
(d) DNA

23. Koshland’s theory of enzyme action is known as

(a) Lock and key theory
(b) Reduced fit theory
(c) Induced fit theory
(d) Enzyme coenzyme theory

24. Concanavalin A is:

(a)  a pigment
(b)  an alkaloid
(c)  an essential oil
(d) a lectin

25. “Ramachandran plot” is used to confirm the structure of

(a) RNA
(b) Proteins
(c) Triacylglycerides
(d) DNA


 1. Answer: (c) end products

Explanation: Feedback inhibition is a mechanism in which an enzyme’s activity is inhibited by the enzyme’s end product. It takes place in an allosteric enzyme that possesses both allosteric and active sites. It can show the mechanism of enzyme action. 

2. Answer: (a) lowering activation energy

Explanation: Enzymes (and other catalysts) act by reducing the activation energy, thereby increasing the rate of reaction.

3. Answer: (d) Both Assertion and Reason are false

Explanation: Unsaturated fatty acids are those which have the presence of one or more double bonds in the fatty acid chain. According to the assertion, arachidic acid is an unsaturated fatty acid. But arachidic acid is a saturated fatty acid. The correct answer is option D i.e. both assertion and reason is incorrect.

4. Answer: (c) Myosin

Explanation: A protein having both structural and enzymatic traits is Myosin.

5. Answer: (b) carbonic anhydrase

Explanation: carbonic anhydrase is one of the fastest enzymes known. Each enzyme molecule can hydrate \(10^6\) molecules of \(Co_2\)per second. This catalyzed reaction is \(10^7\) times as fast as the uncatalyzed one.

6. Answer: (b) Lipids

Explanation:Ester linkages are key components of molecules called lipids. In our bodies, lipids form lipid bilayers, which compose cell membranes and other organelles within the cell.

7. Answer: (a) L-amino acids only

Explanation: All naturally occurring proteins from all living organisms consist of L amino acids. The absolute stereochemistry is related to L-glyceraldehyde, as was the case for triacylglycerides and phospholipids. Most naturally occurring chiral amino acids are S, with the exception of cysteine.

8. Answer: (d) Glucose

Explanation: Glucose is the common monomer of carbohydrates. Carbohydrate helps in providing energy to the body mainly through glucose. Glucose is a simple sugar present in all basic foods.

9. Answer: (a) Collagen

Explanation: Collagen is a fibrous protein that is present in abundance in the human body, being a major constituent of skin, bones as well as various connective tissues. It helps in forming a scaffold to provide strength and structure.

10. Answer: (d) Primary metabolites

Explanation: Primary metabolites are the essential metabolic intermediates of the plants which help in the growth and development of the plant.

11. Answer: (a) amino acids and glucose

Explanation: Massive ions like \(Na^2\)facilitate the absorption of substances like amino acid and glucose through Co transport.

12. Answer: (a) Hydrogen bonds

Explanation: The helical structure of proteins or the alpha helix is the secondary structure of proteins and it is stabilized by hydrogen bonds. In helical structure, the carbonyl oxygen atoms in C = O points in one direction, towards the amide hydrogen atoms in N – H groups, 4 residues away.

13. Answer: (a) lyases

Explanation: Lyases enzyme catalyze the breakage of specific covalent bonds and removal of groups without hydrolysis producing double bonds or removal of double bonds by adding groups e.g., histidine decarboxylase that splits C – C bond of histidine, forming \(CO_2\) and histamine.

14. Answer: (d) 480

Explanation: According to this, if there are 120 adenine, there have to be 120 thymines also present. If there are 120 cytosines, there should be 120 guanines also present. So there are in total 480 nucleotides in the given segment.

15. Answer: (b) isoenzymes

Explanation: Enzymes having slightly different molecular structures but performing identical activities are called isoenzymes. Over 100 enzymes are known to have isoenzymes. Apoenzyme is an inactive enzyme that must associate with a specific cofactor molecule or ion in order to function.

16. Answer: (d) uracil

Explanation: DNA (top) includes thymine (red); in RNA (bottom), thymine is replaced with uracil (yellow).

17. Answer: (a) GATCAATGC

Explanation: The pyrimidine bases are thymine, cytosine, and uracil. In GATCAATGC, four pyrimidine bases are present, two thymines and two cytosines.

18. Answer: (b) RNA

Explanation: RNA (Ribonucleic acid) is distributed more widely in a cell. RNA is a single-stranded molecule, which may have few loops.

19. Answer: (a) rRNA

Explanation:  Ribosomal ribonucleic acid (rRNA) is the most abundant type of RNA. It constitutes the material inside the ribosome and directly helps in the translation of mRNA into proteins.

20. Answer: (d) Glycine

Explanation: Glycine is the simplest amino acid and most commonly found in animal proteins.

21. Answer: (d) \(\alpha\)helix

Explanation:  The \(\alpha\)helix, (\beta\)strand and sheet, and turn are the most prevalent elements of protein secondary structure, which is stabilized by hydrogen bonds between atoms of the peptide backbone.

22. Answer: (a) tRNA

Explanation: An anticodon is found at one end of a transfer RNA (tRNA) molecule. During protein synthesis, each time an amino acid is added to the growing protein, a tRNA forms base pairs with its complementary sequence on the mRNA molecule, ensuring that the appropriate amino acid is inserted into the protein.

23. Answer: (c) Induced fit theory

Explanation: Koshland proposed the induced fit theory in 1958. Part of an enzyme where substrate molecules get attached is known as an active site.

24. Answer: (d) a lectin

Explanation: Concanavalin A (ConA), a lectin with mannose specificity that can induce acute hepatic inflammation, was tested for its therapeutic effect against hepatoma. ConA is cytotoxic or inhibitory to hepatoma cells, which is mediated by the autophagic pathway through mitochondria.

25. Answer: (b) Proteins

Explanation: By making a Ramachandran plot, protein structural scientists can determine which torsional angles are permitted and can obtain insight into the structure of peptides.

Click the below links to practice Biomolecules MCQ Questions for Class 12 

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