In this series of metabolic reaction, Compound R is converted into Compound A, and Enzyme X then catalyzes the conversion of Compound A into Compounds B and D.
Compound B is converted to Compound C.

Assume that Compound Cinhibits Enzyme X and that Compound C is not consumed
in a subsequent reaction. As the concentration of Compound C increases, the rate of
production of which compound is LEAST likely to decrease?
A. Compound A
B. Compound B
C. Compound C
D. Compound D

A. Compound A

Explanation:

Enzymes are specialized, folded proteins that act as biological catalysts- they speed up the rate of certain chemical reactions in biological systems. Enzymes bind to substrates like compound A to their active site, where they facilitate the modification of molecular strutures, creating new compounds.

Inhibitors like compound C can prevent enzyme-substrate binding activity; the chemical reactions do not occur because the substrates cannot gain access to the active site. Because enzymes show specificity, binding only to certain substrates, other molecules cannot be catalysed by the enzyme.

Here, the amount of Compound A, which is produced via the conversion of R, is increased due to the reaction inhibition- its conversion to B and D is not mediated by X, the inhibited enzyme. While conversion may still occur slowly, without its catalyst,  more of the compound is being converted from R to A than A to B and D.

The concentration of A is least likely to decrease.