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 statements is/are correct about amino acids?

  1. Alanine, valine, leucine, and isoleucine have aromatic hydrocarbon side chains.
  2. Methionine has a thiol ether side chain that resembles an n-butyl group in many of its physical properties.
  3. Proline has conformational constraints imposed by the cyclic nature of its pyrrolidine side chain.

  1. Only 1

  2. Only 2

  3. Only 3

  4. Both 2 and 3

  5. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Both option 2 and 3 are correct.

Multiple choice

Which of the following statements about the Fischer convention of amino acids nomenclature is/are correct?

  1. This configuration system of the groups was introduced about an asymmetric center of aspirin.
  2. Horizontal bonds extend above and vertical bonds extend below the plane of the paper.
  3. All amino acids derived from proteins have the L-stereochemical configuration.

  1. Only 1

  2. Only 2

  3. Only 3

  4. Both 1 and 2

  5. Both 2 and 3
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Both statements 2 and 3 are correct.

Multiple choice

Which of the following statements about some uncommon amino acid residues is/are correct?

  1. Amino acid residues- 4-hydroxyproline and 5-hydroxylysine are important structural constituents of collagen.
  2. Histones have specifically methylated, acetylated, and/or phosphorylated Lys, Arg and Ser residues.
  3. N-formylmethionine is initially the N-terminal residue of all prokaryotic proteins.
  4. Gamma-carboxyglutamic acid is a constituent of several proteins involved in blood clotting.

  1. Only 1

  2. Only 2 and 3

  3. Only 3 and 4

  4. Only 2, 3 and 4

  5. All of the above
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

All these statements are correct.

Multiple choice

Find the correct match of amino acid residue with its function.

  1. Gamma-aminobutyric acid: a glutamatedecarboxylation product: neurotransmitters
  2. Dopamine: tyrosine derivative: fatty acid metabolism intermediate
  3. Histamine: histidine decarboxylation product: local mediator of allergic reactions
  4. Thyroxine: a tryptophan derivative: an iodine-containing thyroid hormone

  1. Only 1

  2. Only 1 and 3

  3. Only 4

  4. Only 2

  5. All of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Both these statements are correct.

Multiple choice

Which of the following is not a protein?

  1. Antibody

  2. Insulin

  3. Pepsin

  4. NAD+
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Antibodies, insulin, and pepsin are proteins. NAD+ (Nicotinamide adenine dinucleotide) is a coenzyme, not a protein.

Multiple choice

Which one of the following is a vitamin?

  1. Pepsin

  2. Carotene

  3. Keratin

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

Carotene (specifically beta-carotene) is a pigment that the body converts into Vitamin A, making it a provitamin.

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 are members of the B-complex vitamin group.