Question

The scientist measured the uptake of oxygen by the mitochondria during the investigation. Why did the uptake of oxygen decrease when malonate was added?

A) Malonate directly inhibits oxygen uptake.
B) Malonate prevents the breakdown of glucose.
C) Malonate inhibits the Krebs cycle, reducing the need for oxygen.
D) Malonate interferes with the electron transport chain, reducing oxygen consumption.

Answer 1

Malonate acts as a competitive inhibitor of succinate dehydrogenase, reducing the breakdown of succinate and leading to a decrease in oxygen uptake by the mitochondria.

Step-by-step explanation:

Inhibition of the electron transport chain can have significant effects on oxygen uptake and ATP synthesis. In the case of malonate, it acts as a competitive inhibitor of succinate dehydrogenase, an enzyme involved in the Krebs cycle. By binding to the active site of this enzyme, malonate prevents the breakdown of succinate, leading to a decrease in the overall oxygen uptake by the mitochondria.