Question

The Q cycle can

A) transport protons out of the matrix without additional electron transfer between complexes I and III.
B) associate with complex IV.
C) transfer electrons to O2.
D) generate superoxide.
E) All of the above can be performed by the Q cycle.

Answer 1

The Q cycle can transport protons out of the matrix without additional electron transfer between complexes I and III and plays a role in transferring electrons to O2 but within complex IV. It does not normally generate superoxide.

Step-by-step explanation:

The Q cycle is involved in the electron transport chain (ETC) and has several roles. Specifically, it transports protons out of the matrix without additional electron transfer between complexes I and III. This is because complex III, which is part of the Q cycle, pumps protons into the intermembrane space while passing electrons from Q (ubiquinone) to cytochrome c (Cyt c). Additionally, the Q cycle is also responsible for transferring electrons to O2, but this occurs in complex IV, not within the Q cycle itself.