Question

Indicate whether the following statements are true or false. If a statement is false, explain why it is false.

A. Feedback inhibition is defined as a mechanism of down-regulating enzyme activity by the accumulation of a product earlier in the pathway.
B. If an enzyme's allosteric binding site is occupied, the enzyme may adopt an alternative conformation that is not optimal for catalysis.
C. Protein phosphorylation is another way to alter the conformation of an enzyme and serves exclusively as a mechanism to increase enzyme activity.
D. GTP-binding proteins typically have GTPase activity, and the hydrolysis of GTP transforms them to the "off" conformation.

Answer 1

A. False. Feedback inhibition occurs with the accumulation of a product later in the pathway. B. If an enzyme's allosteric binding site is occupied, it can adopt a suboptimal conformation. C. False. Protein phosphorylation can either increase or decrease enzyme activity. D. True. GTP hydrolysis switches GTP-binding proteins to the "off" conformation.

Step-by-step explanation:

A. False. Feedback inhibition is the mechanism of down-regulating enzyme activity by the accumulation of a product later in the pathway, not earlier.

B. True. If an enzyme's allosteric binding site is occupied, it can adopt an alternative conformation that is not optimal for catalysis.

C. False. Protein phosphorylation can alter the conformation of an enzyme to either increase or decrease its activity.

D. True. GTP-binding proteins typically have GTPase activity, and the hydrolysis of GTP transforms them to the "off" conformation.