In redox reactions, what is the final electron acceptor at the end of the electron transport chain?

• A. Water
• B. NAD+
• C. FAD
• D. Oxygen

Answer: (D)

Verified step by step guidance

1. Understand the concept of the electron transport chain (ETC): It is a series of protein complexes located in the inner mitochondrial membrane that transfer electrons from electron donors to electron acceptors via redox reactions.
2. Recognize that the primary purpose of the ETC is to create a proton gradient across the mitochondrial membrane, which is used to produce ATP through oxidative phosphorylation.
3. Identify the role of electron carriers: NADH and FADH2 donate electrons to the ETC, which are then passed through a series of complexes.
4. Determine the final electron acceptor: In the ETC, electrons are ultimately transferred to oxygen, which combines with protons to form water. This is a crucial step as it allows the continuation of the electron flow and the production of ATP.
5. Conclude that oxygen is the final electron acceptor in the electron transport chain, making it essential for the process of cellular respiration.