Question

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

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

Answer 1

The correct statement about the ETC is that electrons begin with high energy and progressively lose energy at each step, facilitating ATP production.

Step-by-step explanation:

The correct statement about the electron transport chain (ETC) is that electrons start out at very high energy and lose energy at each transfer step. In the ETC, high-energy electrons from NADH and FADH2 move through protein complexes in the inner membrane of mitochondria. During the transfer process, energy is released which is used to pump hydrogen ions across the inner mitochondrial membrane, creating an electrochemical gradient. This gradient then drives the synthesis of ATP as electrons ultimately reduce oxygen to form water. Hence, the process involves sequential energy release and ATP production.

The electron transport chain (ETC) is a series of molecules and protein complexes that transfer high-energy electrons from NADH and FADH2 to oxygen, the final electron acceptor. As the electrons flow through the chain, some of their energy is used to pump hydrogen ions across the inner membrane of the mitochondria, creating an electrochemical gradient. The electrons from the final protein of the ETC are gained by the oxygen molecule, reducing it to water. Therefore, statement 1 is correct, as electrons start out at high energy and lose energy at each transfer step.