Questions and answers for exam Preparation

MCQs

Total Questions : 191 | Page 4 of 20 pages

Question 31. Numerous antibodies can be prepared, against one antigen, each binds to unique epitopes. How is this antibody diversity generated?

By rearrangements of the DNA encoding the variable regions of the heavy and light chains
By the combination of different heavy and light chains that form the antigen binding site
Antibody proteins can physically change their shape to bind different epitopes
Both (a) and (b)

Discuss Question

Answer: Option D. -> Both (a) and (b)
Answer: (d).Both (a) and (b)

Question 32. Which of the following is correct for isoantigens?

They are antigens found in all members of different species
They are antigens found in some members of a species
They are antigens found in all members of a species
They are antigens found in some members of different species

Discuss Question

Answer: Option B. -> They are antigens found in some members of a species
Answer: (b).They are antigens found in some members of a species

Question 33. An exergonic reaction is one that

requires energy to proceed
releases energy for work
gives off much heat
looses energy

Discuss Question

Answer: Option B. -> releases energy for work
Answer: (b).releases energy for work

Question 34. If the free energy change (ΔG) in a reaction is a negative value, it indicates that the

reaction releases energy
reaction absorbs energy
reaction is in negative direction
reaction is in positive direction

Discuss Question

Answer: Option A. -> reaction releases energy
Answer: (a).reaction releases energy

Question 35. To a living organism, which of the following has the greatest amount of available energy per molecule?

Discuss Question

Answer: Option A. -> ATP
Answer: (a).ATP

Question 36. In the reaction, C6H12O6+ 6O2 → 6CO2 + 6H2O + energy, which component is being oxidized?

C6H12O6
O2
CO2
H2O

Discuss Question

Answer: Option A. -> C6H12O6
Answer: (a).C6H12O6

Question 37. Which of the following is the best evidence for the lock and key theory of enzyme action?

Compounds similar in structure to the substrate inhibit enzyme activity
Enzymes are found in living organisms and speed up certain reactions
Enzymes speed up reactions by definite amounts
Enzymes determine the direction of a reaction

Discuss Question

Answer: Option A. -> Compounds similar in structure to the substrate inhibit enzyme activity
Answer: (a).Compounds similar in structure to the substrate inhibit enzyme activity

Question 38. The fact that β-oxidation of fatty acids, occurs in the mitochondria whereas fatty acid synthesis occurs in the cytoplasmic matrix, is an example of regulation of enzymatic activity by the __________ mechanism.

compartmentation
induction
competitive inhibition
repression

Discuss Question

Answer: Option D. -> repression
Answer: (d).repression

Question 39. In the reaction, C6H12O6 + 6O2 → 6CO2 + 6H2O + energy, which component is being reduced?

O2
CO2
H2O
Energy

Discuss Question

Answer: Option A. -> O2
Answer: (a).O2

Question 40. Anthranilate synthase, the first enzyme of tryptophan biosynthesis after the branch point shows feedback inhibition and repression due to