Question

Which of the following statements is true about the electron transport chain?

A. Electrons start out at very high energy and lose energy at each transfer step.
B. Electrons start out at very low energy and gain energy at each transfer step.
C. Electrons gain and release energy as they move from one complex to another
in the electron transport chain.

Answer 1

The correct statement is that electrons start with high energy and lose energy at each step in the ETC, transferring from high to low reduction potentials, and creating an electrochemical gradient used to synthesize ATP.

Step-by-step explanation:

The correct answer to the question about the electron transport chain (ETC) is: A. Electrons start out at very high energy and lose energy at each transfer step. During the process of oxidative phosphorylation, high-energy electrons from NADH and FADH2 are transferred through a series of protein complexes embedded in the inner mitochondrial membrane. In each step of the ETC, the electrons move from a substance with a higher reduction potential to one with a lower reduction potential, releasing energy in each step. This energy is used to pump protons across the inner mitochondrial membrane, creating an electrochemical gradient. The electrochemical gradient facilitates the synthesis of ATP by ATP synthase through a process called chemiosmosis.