Questions and answers for exam Preparation

MCQs

Total Questions : 191 | Page 5 of 20 pages

Question 41. A substrate binds to its enzyme at a location called the __________ site.

coenzyme
substrate
active
polypeptide

Discuss Question

Answer: Option C. -> active
Answer: (c).active

Question 42. The affinity of an enzyme for its substrate, when the enzyme has a Km of 0.50 M will be __________ than the affinity of an enzyme for its substrate when the enzyme has a Km of 0.05 M.

greater
lesser
approximately equal
half

Discuss Question

Answer: Option B. -> lesser
Answer: (b).lesser

Question 43. Hydrogen and oxygen release enormous amounts of energy when they react. Yet, hydrogen and oxygen can be mixed together in a balloon and nothing will happen. Why?

Competitive inhibitors are blocking the reaction from occurring in the active site
There must be contaminating elements in the balloon that prohibit the reaction from occurring
The energy of activation to form the transition-state complex is too high to allow the reaction to occur without assistance
all of the above

Discuss Question

Answer: Option A. -> Competitive inhibitors are blocking the reaction from occurring in the active site
Answer: (a).Competitive inhibitors are blocking the reaction from occurring in the active site

Question 44. An enzyme that is always produced, regardless of the presence of substrates or the end products, is called

a constitutive enzyme
an isoenzyme
a repressible enzyme
an allosteric enzyme

Discuss Question

Answer: Option A. -> a constitutive enzyme
Answer: (a).a constitutive enzyme

Question 45. Adenosine triphosphate is a type of

fatty acid
amino acid
nucleotide
steroid

Discuss Question

Answer: Option C. -> nucleotide
Answer: (c).nucleotide

Question 46. About 7.3 kcal/mole are released when

glucose is converted to CO2 and H2O
NAD+ is reduced to NADH
ATP hydrolysis is coupled to sucrose synthesis
the terminal phosphate bond of ATP is broken by hydrolysis

Discuss Question

Answer: Option A. -> glucose is converted to CO2 and H2O
Answer: (a).glucose is converted to CO2 and H2O

Question 47. The ability of CTP to bind to aspartate carbamoyltransferase and shut down the synthesis of more CTP is an example of

enzyme induction
enzyme repression
feedback inhibition of enzyme activity
none of these

Discuss Question

Answer: Option C. -> feedback inhibition of enzyme activity
Answer: (c).feedback inhibition of enzyme activity

Question 48. Oxidation is the

loss of proton
gain of electron
loss of electron
gain of protons

Discuss Question

Answer: Option C. -> loss of electron
Answer: (c).loss of electron

Question 49. Self reactive antibodies are not found in significant concentration in normal serum because

it is impossible to generate a self-reactive antibody
self reactive B cells are killed by CD8 T cells
B cells that are stimulated via their surface bound antibody in the absence of T cell help to commit suicide
self reactive B cells switch to IgA which is all secreted and not present in serum

Discuss Question

Answer: Option C. -> B cells that are stimulated via their surface bound antibody in the absence of T cell help to commit suicide
Answer: (c).B cells that are stimulated via their surface bound antibody in the absence of T cell help to commit suicide

Question 50. Simulation of which of the following will lead to appearance of first antibody to appear following stimulation by an antigen?

Discuss Question

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