Question

A mutation in Complex I decreases the efficiency of the electron transport chain. However, not all components of the electron transport chain are affected by this mutation. Which component of the electron transport chain will remain unaffected by a mutation in Complex I?
a. Ubiquinone
b. Complex II
c. Complex III
d. Complex IV

Answer 1

Answer:

B. Complex II

Explanation:

Electrons Would Only Be Transferred From FADH2 And Fewer Protons Would Be Pumped Into The Intermembrane Space. The Entire Electron Transport Chain Would Stop Functioning.

Answer 2

Answer:

b. Complex II

Explanation:

The electron transport chain is a sequential series of proteins located in the inner membrane of the mitochondria that act to transfer electrons from different members of the transport chain in a series of redox reactions, which is coupled to the movement of protons (H+) across the membrane. Complex I (also called NADH dehydrogenase or NADH- CoQ reductase) accepts electrons from NADH and passes them to Complex III (also known as coenzyme Q reductase), which also receives electrons from Complex II (succinate coenzyme Q reductase). Ubiquinone (Coenzyme Q) accepts electrons from both complex I and complex II and transfer them to complex III. From complex III electrons pass to complex IV through cytochrome c oxidase and finally to molecular oxygen (O2, the final electron acceptor). In consequence, Complex I and Complex II are linked by different pathways to Complex III, thereby it is expected that Complex II remains unaffected by a mutation in Complex I.