How many net ATP molecules are generated from one glucose molecule during the Citric acid cycle? A. 2 B. 12 C.34 D. 68 2 3. How many ATP molecules are generated from one glucose molecule during glycolysis? A.2 B. 12 C.34 D: 68
The Correct Answer and Explanation is:
Correct Answers:
- How many net ATP molecules are generated from one glucose molecule during the Citric Acid Cycle?
Answer: A. 2 - How many ATP molecules are generated from one glucose molecule during glycolysis?
Answer: A. 2
Explanation:
The breakdown of one molecule of glucose in cellular respiration involves multiple stages: glycolysis, the citric acid cycle (also called the Krebs cycle or TCA cycle), and the electron transport chain (ETC). Each stage contributes to the production of ATP, the energy currency of the cell.
Glycolysis is the first step and occurs in the cytoplasm. During glycolysis, one glucose molecule (a 6-carbon sugar) is broken down into two molecules of pyruvate (each containing 3 carbon atoms). In this process, four ATP molecules are produced, but two ATP molecules are used up in the early steps of glycolysis. This results in a net gain of 2 ATP molecules. Additionally, glycolysis also produces 2 molecules of NADH, which are used later in the electron transport chain to generate more ATP.
The Citric Acid Cycle occurs in the mitochondria and processes the products of glycolysis. Each glucose molecule produces two molecules of acetyl-CoA, which enter the cycle one at a time. For each acetyl-CoA, the cycle produces:
- 1 ATP (or GTP, which is equivalent to ATP)
- 3 NADH
- 1 FADH₂
Since there are two acetyl-CoA molecules per glucose, the total ATP from the Citric Acid Cycle is 2 ATP. Most of the energy from this cycle is stored in the high-energy electrons of NADH and FADH₂, which are used in the electron transport chain to produce more ATP.
Summary:
- Glycolysis: Net 2 ATP
- Citric Acid Cycle: Net 2 ATP
- These numbers do not include the ATP generated from NADH and FADH₂ in the electron transport chain.
