In some organisms, an alternative oxidase will accept electrons from ubiquinol and reduce oxygen to water with no associated proton translocation. What would be a consequence of having this oxidase active?
A) decreased rate of NADH reoxidation
B) decreased P:O ratio
C) decreased rate of oxygen consumption
D) inhibition of oxidative pathways like the citric acid cycle
E) increased sensitivity to cyanide poisoning

Question

Quizplus · Accepted Answer

The P:O ratio is the ratio of ATP molecules synthesized to oxygen molecules consumed. Since the alternative oxidase reduces oxygen without pumping protons, ATP synthesis would decrease in proportion to the oxygen consumed, resulting in a decreased P:O ratio.

In Some Organisms, an Alternative Oxidase Will Accept Electrons from Ubiquinol