Biology · Chemistry

Biomolecules and Enzymes

1,501 Questions

This topic focuses on biomolecules, specifically proteins, enzymes, and amino acids. It includes questions on enzyme structures, protein folding, and catalysis. These concepts are crucial for medical and biology competitive exams.

Enzyme catalysisProtein structuresAmino acid synthesisPolypeptide chainsBiomolecule properties

Biomolecules and Enzymes Questions

Multiple choice

Which of the following matches of metalloenzyme and metal cofactors are incorrect? P. Tyrosinase : Copper Q. Urease : Copper R. Dopamine β-hydroxylase : Nickel S. Catechol dioxygenase : Iron

  1. Only P and Q

  2. Only P and S

  3. Only Q and R

  4. Only Q and S

  5. Only R and S
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Urease is a nickel containing metalloenzyme of high molecular weight that catalyses the hydrolysis of urea into carbon dioxide and ammonia. Dopamine β-hydroxylase is a copper containing enzyme that synthesises norepinephrine from dopamine.

Multiple choice

Which of the following are examples of iron-sulphur proteins?

  1. Rubredoxin
  2. Methane monooxygenase
  3. Rieske proteins
  4. Aconitase

  1. 1 and 2 only

  2. 1, 2 and 3 only

  3. 1, 3 and 4 only

  4. 2 and 3 only

  5. 2, 3 and 4 only
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Rubredoxin is a small iron-sulphur protein found in various sulphur-metabolising bacteria. Rieske proteins are iron-sulphur protein components of cytochrome bc1 complexes and cytochrome b6f complexes, which were first discovered and isolated by John S. Rieske and co-workers in 1964. Aconitase is an iron-sulphur protein that catalyses the interconversion of citrate and isocitrate.

Multiple choice

Which of the following statements is/are true about spheroproteins?

P. Spheroproteins form adducts in water, unlike fibrous or membrane proteins. Q. The spherical structure is induced by the protein's tertiary structure. R. Globular proteins have a mechanism for protein folding, which is nucleation condensation model.

  1. Only P

  2. Only Q

  3. Only R

  4. Only P and Q

  5. Only P and R
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

This option is correct because spherical structure is induced by the protein's tertiary structure.

Multiple choice

Which of the following statements is/are incorrect about acute-phase proteins?

A. The liver responds by producing a large number of acute-phase proteins. B. Positive acute-phase proteins serve similar physiological functions for the immune system. C. Negative acute-phase proteins decrease inflammation.

  1. Only A

  2. Only B

  3. Only C

  4. Only A and B

  5. Only B and C
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

This option is correct. Positive acute-phase proteins serve different physiological functions for the immune system.

Multiple choice

Which of the following statements is/are correct? a. Growth in non living things is reversible. b. Growth in living things takes place by the addition of protoplasm. c. Respiration occurs day and night in all living things.

  1. Only a

  2. Only a and b

  3. Only a and c

  4. Only b and c

  5. Only a, b and c
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

All these are correct statements. Growth in living things is external and is thus, reversible. Growth in living beings is internal and takes place by the addition of new body material called protoplasm. Respiration occurs in living beings day and night.

Multiple choice

Which one of the following is a vitamin?

  1. Pepsin

  2. Parotene

  3. Keratin

  4. Progesterone
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The term 'Parotene' is likely a typographical error for 'Carotene' or a similar compound, but in the context of these options, it is the only one intended to represent a vitamin-like substance. Pepsin is an enzyme, Keratin is a structural protein, and Progesterone is a hormone.

Multiple choice

Which one of the following is a protein?

  1. Ppsin

  2. Carotene

  3. Keratin

  4. Progesterone
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Keratin is a fibrous structural protein that makes up the outer layer of human skin, hair, and nails. Carotene is a pigment, progesterone is a steroid hormone, and "Ppsin" appears to be a typo for pepsin (which is also an enzyme/protein, but misspelled here).

Multiple choice

Which pair contains vitamins of B-group?

  1. Riboflavin and tocopherol

  2. Niacin and thiamine

  3. Thiamine and calciferol

  4. Riboflavin and retinol
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Niacin is Vitamin B3 and Thiamine is Vitamin B1. Both belong to the B-complex group of vitamins.

Multiple choice

The protein part of an enzyme is called

  1. apoenzyme

  2. prosthetic group

  3. coenzyme

  4. cofactor
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

An apoenzyme is the protein component of an enzyme that is inactive until combined with a cofactor or coenzyme.

Multiple choice

Milk contains the protein:

  1. casein

  2. globulin

  3. albumin

  4. histone
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Casein is the primary protein found in milk, accounting for about 80 percent of the total protein content.