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 is a component of myosin?

  1. Creatine

  2. 4-hydroxyproline

  3. γ-carboxyglutamate

  4. Desmosine

  5. 6-N methyl lysine
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

6-N methyl lysine is a component of myosin, which is the contractile protein found in muscles. 6-N methyl lysine is an amino acid which occurs naturally in biofluids of human beings.

Multiple choice

What does an α-helix signify?

  1. Aggregation of protein.

  2. Tertiary structure of protein.

  3. Secondary structure of protein.

  4. Primary structure of protein.

  5. None of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The secondary structure of protein is formed by the folding of linear polypeptide chain into regular structure. The folding of polypeptide chain occurs because NH and CO group in the peptide chain are linked with hydrogen bonds. The α-helix is a rod-like structure. There is an imaginary axis at the middle of the helix. Around the imaginary axis, the polypeptide chain is wound tightly.

Multiple choice

Which of the following is a simple protein?

  1. Keratin

  2. Chymotripsinogen

  3. Glycoproteins

  4. Lipoproteins

  5. Myoglobulin
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Depending on the composition, simple proteins are those proteins, which consist of amino acid residues only. They do not contain any other chemical components. Chymotripsinogen is one such simple protein.

Multiple choice

Depending on polarity and charge of R groups match the following amino acids: Name Type

  1. Glycine A. Polar Uncharged amino acid
  2. Glutamine B. Non-polar aliphatic amino acid
  3. Tyrosine C. Negatively charged amino acid
  4. Glutamate D. Positively charged amino acid
  5. Histidine E. Aromatic amino acid

  1. 1 - B, 2 - D, 3 - E, 4 - C, 5 - A

  2. 1 - B, 2 - A, 3 - E, 4 - C, 5 - D

  3. 1 - C, 2 - A, 3 - E, 4 - B, 5 - D

  4. 1 - B, 2 - D, 3 - E, 4 - A, 5 - C

  5. 1 - B, 2 - E, 3 - D, 4 - C, 5 - A
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Non-polar aliphatic amino acids have hydrophobic and non-polar R groups. Glycine is a non-polar aliphatic amino acid. Polar uncharged amino acids have hydrophilic R groups. Glutamine is a polar uncharged amino acid. Aromatic amino acids are non-polar and contain aromatic side chains. Tyrosine is an aromatic amino acid. Negatively charged amino acids possess R groups with net negative charge. Glutamate is a negatively charged amino acid. Positively charged amino acids have R groups, which are hydrophilic and with positive charge. Histidine is a positively charged amino acid.

Multiple choice

One molecule of secretory IgA can at most bind to _____.

  1. 10 molecules of Ag

  2. 4 molecules of Ag

  3. 2 molecules of Ag

  4. 1 molecules of Ag

  5. 5 molecules of Ag
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

IgA is a dimer where 2 four-chain units are held together by the J chain through disulfide bridges. Each four chain unit has 2(paratopes) antigen binding sites. Thus 2 four chain unit is capable of binding 4 Ag molecules.

Multiple choice

What is the type of interaction between this particular Ag with 4 epitopes and the IgG Ab?

In an antigen antibody interaction, in the zone of equivalence, the isolated antigen IgG complex was found to be in the molar ratio of Antigen : IgG = 2 : 1

  1. Affinity

  2. Cross reactivity

  3. Avidity

  4. Alloreactivity

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

Avidity when the Ag consists of many epitopes (here 4) are mixed with Ab (here IgG) having multiple (here 2) binding sites, the interaction of such type between multivalent Ab and Ag is called, the Avidity.

Multiple choice

Which of the following statements are true regarding transamination?

P. Transamination means transfer of amide nitrogen from a donor molecule to an acceptor molecule. Q. Liver is the main site for transamination. R. Transamination reactions are irreversible. S. Transamination reactions are catalysed by aminotransferases.

  1. P and Q

  2. P and R

  3. P and S

  4. Q and R

  5. Q and S
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

This option is correct because liver is the main site for transamination and transamination reactions are catalysed by aminotransferases (transaminases).

Multiple choice

For the identification of which of the following entities is Sanger’s reagent?

  1. N-terminal of a peptide chain

  2. C-terminal of a peptide chain

  3. Side chain of amino acid

  4. Molecular weight of the peptide chain

  5. Number of amino acids in the peptide chain
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

This option is correct because Sanger’s reagent is use for determining the N-terminal amino acid in peptide chains, in particular insulin.