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

Serum albumin in human blood is:

  1. simple protein

  2. complex protein

  3. conjugated protein

  4. none of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Serum albumin is a simple protein because it consists only of amino acids without any non-protein prosthetic groups. Conjugated proteins require a non-protein component.

Multiple choice

Which of the following is a pair of zinc containing enzymes?

  1. Carboxypeptidase and ATPase

  2. Carbonic anhydrase and Phosphoglucomutase

  3. Carbonic anhydrase and Carboxypeptidase

  4. ATPase and Phosphoglucomutase

  5. Phosphoglucomutase and Carboxypeptidase
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Carboxypeptidase and carbonic anhydrase are zinc containing enzymes.

Multiple choice

Which of the following statements are false?

  1. All transferrins are lipoproteins.
  2. The transport of iron from storage sites in cellular ferritin or hemosiderin occurs via the serum-transport protein transferrin.
  3. Each transferrin binds only one iron atom.
  4. The protein coat of ferritin is a hollow sphere of 24 polypeptide chains.

Select the correct answer using codes given below:

  1. 1 and 2

  2. 1 and 3

  3. 1 and 4

  4. 2 and 3

  5. 3 and 4
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

All transferrins are glycoproteins. Although transferrins have a high molecular weight, they bind only two iron atoms.

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 FALSE regarding enzymes?

  1. The term enzyme was proposed by Kuhne.

  2. The first enzyme molecule to be isolated in pure crystalline form was urease.

  3. Synthesis of enzymes is regulated by inducer and repressor genes.

  4. DNA ligase is first isolated from bacteriophages.

  5. Ribozyme is RNA with enzyme activity.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Synthesis of enzymes is regulated by operator and regulator genes.