What are the reactants in the process of cellular respiration?

• A. Glucose and oxygen
• B. NADH and FADH2
• C. ATP and oxygen
• D. Carbon dioxide and water

Answer: (A)

Verified step by step guidance

1. Understand the process of cellular respiration, which is a series of metabolic reactions that convert biochemical energy from nutrients into adenosine triphosphate (ATP), and then release waste products.
2. Identify the main stages of cellular respiration: glycolysis, the citric acid cycle (Krebs cycle), and oxidative phosphorylation.
3. Recognize that glycolysis, the first stage, begins with glucose, which is broken down into pyruvate, producing a small amount of ATP and NADH.
4. In the presence of oxygen, pyruvate enters the mitochondria where it is further oxidized in the citric acid cycle, producing more NADH and FADH2, which are electron carriers.
5. During oxidative phosphorylation, NADH and FADH2 donate electrons to the electron transport chain, where oxygen acts as the final electron acceptor, forming water. This process generates a large amount of ATP.