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

• A. The electron transport chain is responsible for producing ATP through oxidative phosphorylation.
• B. The electron transport chain directly produces glucose from carbon dioxide and water.
• C. The electron transport chain occurs in the cytoplasm of eukaryotic cells.
• D. Oxygen is not required for the electron transport chain to function.

Answer: (A)

Verified step by step guidance

1. Begin by understanding the role of the electron transport chain (ETC) in cellular respiration. The ETC is the final stage of aerobic respiration, occurring in the inner mitochondrial membrane of eukaryotic cells.
2. Recognize that the primary function of the ETC is to facilitate oxidative phosphorylation, which is the process of generating ATP. This occurs as electrons are transferred through a series of protein complexes and coenzymes.
3. Clarify that the ETC does not directly produce glucose. Instead, it is involved in the production of ATP, using electrons derived from NADH and FADH2, which are generated in earlier stages of cellular respiration.
4. Understand the location of the ETC. It occurs in the inner mitochondrial membrane, not in the cytoplasm. This is crucial for the establishment of a proton gradient necessary for ATP synthesis.
5. Acknowledge the importance of oxygen in the ETC. Oxygen acts as the final electron acceptor, allowing the chain to function properly. Without oxygen, the ETC cannot operate, and ATP production is halted.