Fig. 2.1 shows two types of enzyme inhibition. In one type, both the substrate and an inhibitor are able to bind directly to the enzyme's active site, so the inhibitor competes with the substrate for that site. What is this type of inhibition called?
AAllosteric inhibition, where a regulatory molecule binds a site away from the active site
BFeedback inhibition, where the pathway's final product inhibits an enzyme earlier in the sequence
CCompetitive inhibition, where the inhibitor also binds directly at the enzyme's active site
DNon-competitive inhibition, where the inhibitor binds a separate site and alters the active site's shape
Explanation
The inhibitor has a shape similar to the substrate and binds the same active site, directly competing with the substrate for that site; this direct competition for the active site is what defines competitive inhibition.
Derived from ZIMSEC Biology Paper 2, June 2006, Q1