Biomolecules Class 11 Biology - MCQ Questions based on NCERT

This article contains NCERT based 45 MCQ questions test on Biology chapter "Biomolecules". These questions are highly valuable for the NEET exam. You can attempt these questions in the form of an interactive quiz and calculate your score. Read the below quiz rules carefully before you start

General Instructions

• Quiz contains 45 questions of 4 marks each.
• Correct answer (✔) will award you +4 marks and Incorrect answer (✘) will give you -1 mark.
• Total test is of 180 marks.
• Tap on box in order to select any option that you think is correct.
• Press the Submit button given in the end of quiz to calculate your score.
• There is a PDF file attached in the end of quiz. You can see detailed solutions to all questions and do self analysis from that file as well. 

Question 1. With reference to enzymes, turnover number means –
(1) the number of substrate molecules that molecule of an enzyme converts into products per minute.
(2) the number of substrate molecules that molecule of an enzyme converts into products per day.
(3) the number of substrate molecules that molecule of an enzyme converts into products per hour.
(4) the number of substrate molecules that molecule of an enzyme converts into products per second.

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Question 2. With reference to enzymes, which one of the following statements is true?
(1) Apoenzyme = Holoenzyme + Coenzyme
(2) Holoenzyme = Apoenzyme + Coenzyme
(3) Coenzyme = Apoenzyme + Holoenzyme
(4) Holoenzyme = Coenzyme − Apoenzyme

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Question 3. _____ are the most abundant proteins in the living world.
(1) Ribozyme of plants and collagen of animals
(2) RuBisCO of plants and collagen of animals
(3) PEP case of plants and keratin of animals
(4) Alcohol dehydrogenase of plants and melanin of animals

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Question 4. Identify this structure:

(1) Adynylic Acid
(2) Uracil
(3) Cholesterol
(4) Adenosine

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Question 5. What is the role of competitive inhibitor during enzyme action?
(1) It alters the active site of the enzyme and prevents the binding of substrate.
(2) It enhances enzyme action.
(3) It inhibits breaking of chemical bonds of the substrate.
(4) It declines the enzyme action.

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Question 6. In a polysaccharide, number of monosaccharides are linked by –
(1) glycosidic bond
(2) peptide bond
(3) hydrogen bond
(4) phosphoester bond

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Question 7. Many elements are found in living organisms either free or in the form of compounds. One of the following is not found in living organisms.
(1) Silicon
(2) Magnesium
(3) Iron
(4) Sodium

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Question 8. Amino acids, as the name suggests, have both an amino group and a carboxyl group in their structure. In addition, all naturally occurring amino acids (those which are found in proteins) are called L-amino acids. From this, can you guess from which compound can the simplest amino acid be made?
(1) Formic acid
(2) Glycerol
(3) Glycolic acid
(4) Glycine

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Question 9. Sugars are technically called carbohydrates, referring to the fact that their formulae are only multiple of C(H₂O). Hexoses therefore have six carbons, twelve hydrogens and six oxygen atoms. Glucose is a hexose. Choose from among the following another hexose.
(1) Fructose
(2) Erythrose
(3) Ribulose
(4) Ribose

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Question 10. When you take cells or tissue pieces and grind them with an acid in a mortar and pestle, all the small biomolecules dissolve in the acid. Proteins, polysaccharides and nucleic acids are insoluble in mineral acid and get precipitated. The acid soluble compounds include amino acids, nucleosides, small sugars etc.

When one adds a phosphate group to a nucleoside one gets another acid soluble biomolecule called
(1) Nitrogen base
(2) Adenine
(3) Sugar phosphate
(4) Nucleotide

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Question 11. When we homogenise any tissue in an acid the acid soluble pool represents
(1) Cytoplasm
(2) Cell membrane
(3) Nucleus
(4) Mitochondria

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Question 12. The most abundant chemical in living organisms could be
(1) Protein
(2) Water
(3) Sugar
(4) Nucleic acid

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Question 13. A homopolymer has only one type of building block called monomer repeated 'n' number of times. A heteropolymer has more than one type of monomer. Proteins are heteropolymers made of amino acids. While a nucleic acid like DNA or RNA is made of only 4 types of nucleotide monomers, proteins are made of
(1) 20 types of monomers
(2) 40 types of monomers
(3) 3 types of monomers
(4) only one type of monomer

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Question 14. Glycogen is a homopolymer made of
(1) Glucose units
(2) Galactose units
(3) Ribose units
(4) Amino acids

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Question 15. The number of 'ends' in a glycogen molecule would be
(1) Equal to the number of branches plus one
(2) Equal to the number of branch points
(3) One
(4) Two, one on the left side and another on the right side

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Question 16. A pure protein should normally have
(1) Two ends
(2) One end
(3) Three ends
(4) No ends

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Question 17. Enzymes are biocatalysts. They catalyze biochemical reactions. In general they reduce activation energy of reactions. Many physico-chemical processes are enzyme mediated. Some examples of enzyme mediated reactions are given below. Tick the wrong entry.
(1) Dissolving CO₂ in water
(2) Untwining the two strands of DNA
(3) Hydrolysis of sucrose
(4) Formation of peptide bond

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Question 18. Component present in both nucleotides & nucleosides is
(1) sugar
(2) phosphate
(3) nitrogenous base
(4) both (1) and (3)

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Question 19. Which of the following statements about amino acids is incorrect?
(1) Essential amino acids are not synthesized in the body, therefore have to be provided in the diet.
(2) Leucine, isoleucine, lysine and valine are essential amino acids.
(3) Cysteine and methionine are sulphur containing amino acids.
(4) Lysine and arginine are acidic amino acids.

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Question 20. The sum total composition of acid soluble and acid insoluble fraction represents the entire composition of
(1) dead cells
(2) gene pool
(3) cellular pool
(4) gene library

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Question 21. An example of aromatic amino acid is
(1) tyrosine
(2) phenylalanine
(3) tryptophan
(4) all of these.

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Question 22. Given molecular formula belongs to which of the following groups of biomolecules?

(1) Carbohydrates
(2) Proteins
(3) Nucleic acids
(4) Triglycerides

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Question 23. Biological molecules are primarily joined by
(1) peptide bonds
(2) ionic bonds
(3) hydrogen bonds
(4) covalent bonds

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Question 24. Which of the following is a triglyceride?
(1) Wax
(2) Phospholipid
(3) Oil
(4) Steroid

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Question 25. Select the option that correctly identifies the chemical bond present in the given biomolecules.
Polysaccharides - A, Proteins - B, Fats - C, Water - D
(1) A-Ester, B-Peptide, C-Glycosidic, D-Hydrogen
(2) A-Glycosidic, B-Peptide, C-Ester, D-Hydrogen
(3) A-Glycosidic, B-Peptide, C-Hydrogen, D-Ester
(4) A-Hydrogen, B-Ester, C-Peptide, D-Glycosidic

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Question 26. In a DNA molecule, the phosphate group is attached to ____ carbon of the sugar residue of its own nucleotide and carbon of the sugar residue of the next nucleotide by bonds.
(1) 5', 3', phosphodiester
(2) 5', 3', glycosidic
(3) 3', 5', phosphodiester
(4) 3', 5', glycosidic

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Question 27. Pyrimidines have nitrogen atoms at _____ positions.
(1) 1', 3', 7', 9'
(2) 1', 5', 7', 9'
(3) 1', 3'
(4) 1', 9'

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Question 28. The correct order of chemical composition of living tissues/cells in term of percentage of the total cellular mass is
(1) Nucleic acid > Proteins > H₂O > Carbohydrates > Ions > Lipids
(2) H₂O > Proteins > Nucleic acid > Carbohydrates > Lipids > Ions
(3) H₂O > Proteins > Carbohydrates > Nucleic acid > Lipids > Ions
(4) Lipids > Ions > Carbohydrates > H₂O > Proteins > Nucleic acid

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Question 29. An α-helix is the example of which type of protein structure?
(1) Primary
(2) Secondary
(3) Tertiary
(4) Quaternary

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Question 30. The polysaccharides made up of glucose monomers are
(1) sucrose, lactose, maltose
(2) chitin, glycogen, starch
(3) starch, glycogen, cellulose
(4) starch, inulin, peptidoglycan.

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Question 31. The regulation by an organism of chemical composition of its blood and body fluids and other aspects of its internal environment so that physiological processes can proceed at optimum rates is called
(1) metabolism
(2) enthalpy
(3) entropy
(4) homeostasis

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Question 32. What is denoted by X and Y in the given graph?

(1) X = Activation energy without enzyme
    Y = Activation energy with enzyme
(2) X = Activation energy with enzyme
    Y = Activation energy without enzyme
(3) X = Substrate concentration with enzyme
    Y = Substrate concentration without enzyme
(4) X = Substrate concentration without enzyme
    Y = Substrate concentration with enzyme

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Question 33. Feedback inhibition of an enzyme is influenced by
(1) enzyme itself
(2) external factors
(3) end product
(4) substrate

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Question 34. Michaelis-Menten Constant (K_m) is equal to
(1) the rate of reaction
(2) the rate of enzymatic activity
(3) substrate concentration at which the reaction attains half of its maximum velocity
(4) substrate concentration at which the rate of reaction is maximum

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Question 35. Inhibition of succinate dehydrogenase by malonate is an example of
(1) non-competitive inhibition
(2) competitive inhibition
(3) allosteric inhibition
(4) negative feedback

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Question 36. Enzymes are most functional at the temperature range of
(1) 15–25°C
(2) 20–30°C
(3) 30–50°C
(4) 50–60°C

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Question 37. Which of the following is an example of isozyme?
(1) α-Amylase
(2) Glucokinase
(3) Lactate dehydrogenase
(4) All of these

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Question 38. Saturated fatty acids possess ____ bonds between carbon atoms and are ____ at room temperature.
(1) single, solids
(2) double, solids
(3) single, liquids
(4) double, liquids

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Question 39. Cytidine is a –
(1) nitrogenous base
(2) nucleoside
(3) nucleotide
(4) nucleic acid

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Question 40. Which of the following is the correct match?

	Acidic amino acid	Basic amino acid	Neutral amino acid
(1)	Glutamic acid	Lysine	Valine
(2)	Lysine	Valine	Glutamic acid
(3)	Glutamic acid	Valine	Lysine
(4)	Lysine	Glutamic acid	Valine

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Question 41. Acidic amino acids have two –COOH groups and one –NH₂ group per molecule. Select the pair that consists of acidic amino acids.
(1) Aspartic acid, glutamic acid
(2) Lysine, arginine
(3) Glycine, alanine
(4) Both (1) and (2)

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Question 42. Which of the following statements is not correct regarding chitin?
(1) It is a storage polysaccharide.
(2) It is a homopolysaccharide.
(3) It is a constituent of arthropod exoskeleton and fungal cell wall.
(4) It is the second most abundant carbohydrate on earth.

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Question 43. Match Column-I with Column-II and select the correct option from the codes given below.

Column-I	Column-II
A. Cotton fibre	(i) Starch
B. Exoskeleton of cockroach	(ii) Glycogen
C. Liver	(iii) Chitin
D. Peeled potato	(iv) Inulin
E. Roots of Dahlia	(v) Cellulose

(1) A-(v), B-(iii), C-(ii), D-(i), E-(iv)
(2) A-(v), B-(iii), C-(i), D-(iv), E-(ii)
(3) A-(i), B-(ii), C-(iii), D-(v), E-(iv)
(4) A-(iii), B-(ii), C-(v), D-(iv), E-(i)

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Question 44. ______ is the most abundant protein in animal world and _____ is the most abundant protein in the whole biosphere.
(1) Collagen, RuBisCO
(2) Collagen, keratin
(3) Keratin, RuBisCO
(4) Keratin, collagen

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Question 45. An unknown liquid collected from a sample of peas is added to a beaker of water and is vigorously shaken. After a few minutes, water and the unknown liquid form two separate layers. To which class of biomolecules does the unknown liquid most likely belong?
(1) Polysaccharides
(2) Proteins
(3) Lipids
(4) Enzymes

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Detailed Solutions

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