Biology · Chemistry

Biomolecules and Enzymes

1,432 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

Match the following Fe containing proteins with their functions and oxidation state of Fe.

   
Fe containing protein
Function
Oxidation state of Fe
P. Hemoglobin i. Plasma O2 transport a. 2
Q. Myoglobin ii. Muscle O2 storage b. 3
R. Transferrin iii. Plasma Fe transport
S. Catalase iv. H2O2 metabolism

  1. P - ii - a, Q - iv - b, R - i - b, S - iii - b

  2. P - iii - a, Q - iv - a, R - ii - b, S - i - b

  3. P - i - a, Q - ii - a, R - iii - b, S - iv - a

  4. P - ii - b, Q - iii - b, R - iv - a, S - i - a

  5. P - i - b, Q - iii - b, R - ii - a, S - iv - b
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Hemoglobin is a plasma O2 transport protein. Oxidation number of Fe in hemoglobin is 2. Myoglobin is a muscle O2 storage protein, Oxidation number of Fe in myoglobin is 2. Transferrin is a plasma Fe transport protein. Oxidation number of Fe in transferrin is 3. Catalase is an enzyme which catalyzes H2O2 metabolism. Oxidation number of Fe in catalase is 2.

Multiple choice

Which of the following is/are examples of endopeptidase?

  1. Trypsin
  2. Chymotrypsin
  3. Pepsin
  4. Carboxpeptidase A Select the correct answer using codes given below:

  1. 1 only

  2. 1 and 4

  3. 1, 2 and 3

  4. 3 and 4

  5. 4 only
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Endopeptidases are proteolytic peptidases that break peptide bonds of nonterminal amino acids. Trypsin is an endopeptidase secreted in an inactive form (trypsinogen) by the pancreas into the duodenum. Chymotrypsin is a serine endopeptidase produced by the acinar cells of the pancreas. Pepsin is an endopeptidase which cleaves peptide linkages formed by amino groups of aromatic and acidic amino acids.

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.