fbpx

MC Q&A

What happens when a K-acting inhibitor is added to an allosteric enzyme system?
A. The apparent KM for the substrate increases.
B. The apparent KM for the substrate decreases.
C. The apparent Vmax for the substrate increases.
D. The apparent Vmax for the substrate decreases.
The concerted model for allosteric behavior was proposed by:
A. Koshland
B. Pauling
C. Pasteur
D. Monod, Wyman and Changeux
E. All of these
Which of the following does not apply to the concerted model for subunit behavior:
A. Each subunit can exist in a relaxed (R) and taut (T) conformation.
B. All subunits will be in either the R or the T conformation at the same time.
C. Some subunits can be in the R state while others are in the T state.
The sequential model for allosteric enzymes was proposed by:
A. Koshland
B. Pauling
C. Pasteur
D. Monod, Wyman and Changeux
E. All of these
Allosteric enzymes must exhibit which of the following?
A. feedback inhibition
B. a phosphorylation site
C. general acid-base catalysis
D. a quaternary structure
The behavior of allosteric enzymes
A. does not play any role in feedback inhibition in metabolic pathways
B. is strongly dependent on the presence of metal ions
C. is related to their ability to hydrolyze themselves
D. depends on changes in their quaternary structure on binding of substrates or inhibitors
In the concerted model for allosteric enzymes
A. the relative affinities of substrate for the T and R conformations plays an important role in the cooperativity of the reaction.
B. the equilibrium between the T and R conformations plays a minor role.
C. the enzymatic activity of the T conformation is considerably higher than that of the R form.
D. it is possible to describe the reactions of all allosteric enzymes accurately.
In the concerted model, which state binds the substrate more tightly?
A. the relaxed (R) state
B. the taut (T) state
C. Both states bind equally well.
Where do allosteric inhibitors bind on an enzyme?
A. They always bind at a site different from the active site.
B. They always bind at the active site.
C. They can bind at either active site or another site.
In reactions catalyzed by allosteric enzymes
A. substrate, activators, and inhibitors all compete for the same binding site on the enzyme.
B. there is no distinction between catalytic and regulatory subunits.
C. the presence of an activator makes the plot of reaction rate against substrate concentration less cooperative.
D. the presence of an inhibitor makes the plot of reaction rate against substrate concentration less cooperative.

Can't find an answer to your question?