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

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

 
 

Multiple choice

What does the secondary structure of proteins mean?

  1. Linear sequence of amino acids belonging to a peptide chain

  2. Folding of linear polypeptide chain into specialised coiled structure

  3. The arrangement and interrelationship of twisted chains into specific loops and bends

  4. Presence of more than one polypeptide chain

  5. Integration of a prosthetic group in the polypeptide chain

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

 
 

Multiple choice

What is the structure of haemoglobin?

  1. Primary

  2. Helical

  3. Tertiary

  4. Quaternary

  5. Amorphous

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

Due to the presence of two polypeptide chains, hemoglobin has a quaternary structure which is a characteristic of many multi-subunit globular proteins.

 
 

Multiple choice

Antibody is formed by:

  1. protein

  2. carbohydrate

  3. nucleic acid

  4. lipid

  5. vitamin
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Antibodies are glycoprotein molecules called immunoglobulins produced by plasma cells. They are composed of amino acid chains arranged in a characteristic Y-shape that specifically bind to antigens.

Multiple choice

Which of the following statements is/are incorrect about phloretin?

  1. Phloretin is obtained from apple leaves.

  2. Phloretin inhibits the transportation of glucose into the cell by SGLT1 and SGLT2.

  3. Phloretin inhibits glucose transportation in large intestine.

  4. Phloretin inhibits urea transport.

  5. Both 1 and 2

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

This option is correct.