Which Statement Best Describes an Electron Transfer Chain

Question

Which statement best describes an electron transfer chain?  
A) It generates energy from carbohydrates.
B) It is used by cells to dispose of excess electrons.
C) It utilizes ATP to synthesize nutrients.
D) It transfers energy, stepwise, from one compound to another.
E) It requires activation by oxygen.

Accepted Answer

An electron transfer chain transfers energy stepwise from one compound to another. It is a series of protein complexes located in the inner mitochondrial membrane, which passes electrons along the chain, releasing energy that is used to generate ATP. The electron transfer chain is an essential part of cellular respiration, which breaks down carbohydrates to generate energy. It does not dispose of excess electrons or synthesize nutrients, nor does it require activation by oxygen (although oxygen is the final acceptor of the electrons in aerobic respiration).