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

When is a peptide bond formed?

  1. During synthesis of proteins

  2. During synthesis of disaccharides

  3. During synthesis of long chain fatty acids

  4. During synthesis of polynucleotides

  5. During synthesis of vitamins
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The bond formed between two amino acids is called peptide bond. A protein molecule is made of many amino acids linked together by peptide bond.

Multiple choice

The level of protein structure represented by the alpha-helix shape is

  1. quaternary

  2. tertiary

  3. secondary

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

The alpha-helix is a type of secondary protein structure. Secondary structure refers to local folding patterns stabilized by hydrogen bonds between the backbone amide and carbonyl groups. The alpha-helix and beta-sheet are the two main types of secondary structure. Primary structure is the amino acid sequence, tertiary is overall 3D folding, and quaternary involves multiple polypeptide chains.

Multiple choice

The process that joins amino acids together to make enzymes is

  1. oxidation

  2. denaturation

  3. dehydration synthesis

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

Dehydration synthesis (also called condensation) joins amino acids by removing a water molecule between them, forming peptide bonds that create polypeptide chains and enzymes. Oxidation involves electron loss, denaturation unfolds proteins, and hydrolysis breaks them down.

Multiple choice

What is an apoenzyme?

  1. Enzyme + prosthetic group

  2. Enzymes having the same function, but a different molecular configuration are called holoenzymes

  3. Inactive form of enzymes

  4. The protein part of an enzyme

  5. Non-protein part of an enzyme

Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The protein part of an enzyme is called apoenzyme, to which the coenzyme attaches to form an active enzyme.

 
 

Multiple choice

What does Michaelis Menten constant Km signifies?

  1. Concentration of substrate

  2. Affinity of an enzyme for its substrate

  3. Both (1) and (2)

  4. It is the t1/2 of the reaction.

  5. The rate at which ES complex dissociates to form the product.

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

 
 

Multiple choice

What is meant by feedback inhibition?

  1. Inhibition of enzyme activity at an active site by an inhibitor which is structurally similar to a substrate

  2. Inhibition of first step of biosynthesis by the end-product of reaction

  3. Inhibition by a structurally different inhibitor at a place other than active site

  4. Denaturation of enzyme

  5. Mixed competitive and non-competitive inhibition

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation