Question

The oxygen-dependent reactions required for cellular respiration were originally

thought to occur in a linear pathway. By using a competitive inhibitor for one
enzyme in the pathway, investigators discovered that these reactions occur in a
cycle. Which product in the reaction pathway builds up when the inhibitor is
added?____
(a) citrate
(b) succinate
(c) fumarate
(d) malate

Answer 1

When a competitive inhibitor is added to succinate dehydrogenase in the Krebs cycle, it causes succinate to accumulate since it cannot be converted into fumarate.

Step-by-step explanation:

The question aims to identify which product in the cellular respiration pathway builds up when a competitive inhibitor is added to one of the enzymes in the cycle. By adding a competitive inhibitor to the enzyme succinate dehydrogenase, we can observe the effects within the Krebs cycle. This enzyme is responsible for converting succinate into fumarate in the cycle. If succinate dehydrogenase is inhibited, it will prevent the conversion of succinate to fumarate, causing succinate to accumulate. Hence, when a competitive inhibitor is added to succinate dehydrogenase, the product that builds up is succinate (option b).