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

Major proteins involved in the production of antibodies are ___________.

  1. albumins

  2. alpha globulins

  3. a-globulins

  4. g-globulins
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Gamma globulins (γ-globulins) are the class of plasma proteins that include immunoglobulins (antibodies). Antibodies are produced by plasma B cells and are essential for the adaptive immune response. Albumins transport substances, while alpha and beta globulins have other functions like transport and enzyme inhibition.

Multiple choice

Which of the following characteristics best applies to the allosteric effector?

  1. It competes with the substrate for the catalytic site.

  2. It binds to a site other than the catalytic site.

  3. It changes the nature of the product formed.

  4. It changes the substrate specificity of the enzyme.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Allosteric enzyme, upon binding an effector, changes its shape, which in turn changes its affinity towards its product. The effector never binds with the catalytic site of the enzyme.

Multiple choice

GABA is derived from which amino acid?

  1. Tryptophan

  2. TYrosin

  3. Glutamate

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

GABA is systhesised from glutamate by the enzyme glutamic acid decarboxylase. It is an inhibitory neurotransmitter.

Multiple choice

Alanine on transamination gives rise to

  1. pyruvic acid

  2. para-hydroxyphenylpyruvate

  3. phenylpyruvate

  4. hydroxypyruvate
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Alanine transaminase transfers its amino group, which forms pyruvate.

Multiple choice

Two proteins are having the same molecular mass and identical pH of 7. The best way to separate them will be

  1. SDS polyacrylamide gel electrophoresis

  2. Native gel electrophoresis

  3. Cation exchange chromatography

  4. Anion exchange chromatography
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

SDS PAGE is not used in if a particular protein has to be separated in the basis of their biological activity. As there is no treatment with SDS, all the proteins will carry their own charge at the pH and will move according to their different electrophoretic mobilities.

Multiple choice

In an enzyme mixture, both substrates and inhibitors have been added. Both of them interact with the same binding site of enzyme What is true in this situation?

  1. Substrate will bind to the active site of the enzyme with no inhibition.

  2. Both substrate and the inhibitor will compete for binding to the catalytic site of the enzyme.

  3. Substrate can never bind itself to the enzyme.

  4. None of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

As both the substrate and the inhibitor share the same binding site in the enzyme, they will compete with each other in binding. This will exert an competitive inhibition. If substarte concentration is increased to a greater level, then the inhibition will be released.

Multiple choice

Which of the following statements is true?

  1. Both cytosolic and extracellular proteins have similar amount of disulphide bonds.

  2. Cytosolic proteins lack disulphide bonds, whereas extracellular proteins have more disulphide bonds.

  3. Extracellular proteins lack disulphide bonds, whereas cytosolic proteins have more disulphide bonds.

  4. None of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The cytosol is a reducing environment whereas the extracellular milieu is an oxidising environment. Disulphide bonds are formed as a result of oxidation of thiol group and it requires an oxidising environment.