The oxygen consumed during cellular respiration is directly involved in which of the following processes or events?
A) accepting electrons at the end of the electron transport chain
B) glycolysis
C) the citric acid cycle
D) the oxidation of pyruvate to acetyl COA.
The correct answer and explanation is :
Correct Answer:
A) Accepting electrons at the end of the electron transport chain
Explanation:
Cellular respiration is a multi-step process that converts glucose into ATP, the cell’s primary energy currency. The three main stages of cellular respiration include glycolysis, the citric acid cycle (Krebs cycle), and the electron transport chain (ETC). Oxygen plays a crucial role in the final stage, the electron transport chain.
During the ETC, electrons from NADH and FADH₂ (produced during glycolysis and the citric acid cycle) are transferred through a series of protein complexes embedded in the inner mitochondrial membrane. As electrons move through these complexes, they create a proton gradient by pumping hydrogen ions (H⁺) into the intermembrane space, which generates potential energy.
Oxygen serves as the final electron acceptor in the electron transport chain. Without oxygen, the ETC would halt, preventing ATP production. At the end of the chain, electrons combine with oxygen and hydrogen ions to form water (H₂O). This reaction is crucial because it maintains the flow of electrons through the ETC and prevents a backup that would stop ATP production.
The other answer choices are incorrect because:
- B) Glycolysis: Occurs in the cytoplasm and does not require oxygen directly.
- C) The citric acid cycle: Takes place in the mitochondrial matrix and generates electron carriers but does not use oxygen directly.
- D) The oxidation of pyruvate to acetyl-CoA: This step produces NADH but does not involve oxygen as an electron acceptor.
Thus, oxygen is essential for efficient ATP production by allowing the electron transport chain to function properly.
Image:
Generating an image of the electron transport chain…
