At The Complete End Of Cellular Respiration, How Many Molecules Of ATP Are Produced?A) 26 B) 15 C) 38 D) 34
Cellular respiration is a complex process that involves the breakdown of glucose and other organic molecules to produce energy in the form of ATP (adenosine triphosphate). This process occurs in three stages: glycolysis, the citric acid cycle, and oxidative phosphorylation. In this article, we will delve into the final stage of cellular respiration and explore how many molecules of ATP are produced at the end of this process.
The Three Stages of Cellular Respiration
Before we dive into the final stage of cellular respiration, let's briefly review the three stages involved in this process.
Glycolysis
Glycolysis is the first stage of cellular respiration, where glucose is broken down into pyruvate. This process occurs in the cytosol of the cell and produces a net gain of 2 ATP molecules and 2 NADH molecules.
The Citric Acid Cycle
The citric acid cycle, also known as the Krebs cycle or tricarboxylic acid (TCA) cycle, is the second stage of cellular respiration. This process takes place in the mitochondria and produces a net gain of 2 ATP molecules, 6 NADH molecules, and 2 FADH2 molecules.
Oxidative Phosphorylation
Oxidative phosphorylation is the final stage of cellular respiration, where the energy from NADH and FADH2 is used to produce ATP. This process occurs in the mitochondria and is the most efficient way to produce ATP.
The Final Stage of Cellular Respiration: Oxidative Phosphorylation
In oxidative phosphorylation, the energy from NADH and FADH2 is used to produce ATP through a process called chemiosmosis. This process involves the movement of protons (H+ ions) across the mitochondrial inner membrane, creating a proton gradient. The energy from this gradient is used to produce ATP through the process of ATP synthase.
How Many Molecules of ATP are Produced?
Now that we have reviewed the final stage of cellular respiration, let's explore how many molecules of ATP are produced at the end of this process. In oxidative phosphorylation, each NADH molecule produces 2.5 ATP molecules, and each FADH2 molecule produces 1.5 ATP molecules.
Assuming that 10 NADH molecules and 2 FADH2 molecules are produced in the citric acid cycle, we can calculate the total number of ATP molecules produced in oxidative phosphorylation as follows:
- 10 NADH molecules x 2.5 ATP molecules/NADH = 25 ATP molecules
- 2 FADH2 molecules x 1.5 ATP molecules/FADH2 = 3 ATP molecules
- Total ATP molecules produced = 25 + 3 = 28 ATP molecules
However, this is not the final answer. We also need to consider the ATP molecules produced in glycolysis and the citric acid cycle. In glycolysis, 2 ATP molecules are produced, and in the citric acid cycle, 2 ATP molecules are produced. Therefore, the total number of ATP molecules produced at the end of cellular respiration is:
- 28 ATP molecules (from oxidative phosphorylation) + 2 ATP molecules (from glycolysis) + 2 ATP molecules (from the citric acid cycle) = 32 ATP molecules
However, this is still not the final answer. We also need to consider the ATP molecules produced in the electron transport chain. In the electron transport chain, the energy from NADH and FADH2 is used to produce ATP through a process called chemiosmosis. This process produces an additional 2 ATP molecules.
Therefore, the total number of ATP molecules produced at the end of cellular respiration is:
- 32 ATP molecules + 2 ATP molecules = 34 ATP molecules
Conclusion
In conclusion, the final stage of cellular respiration, oxidative phosphorylation, produces a total of 34 molecules of ATP. This is the highest yield of ATP molecules produced in any stage of cellular respiration. The energy from NADH and FADH2 is used to produce ATP through a process called chemiosmosis, which involves the movement of protons across the mitochondrial inner membrane and the production of ATP through the process of ATP synthase.
Answer
The correct answer is D) 34.
References
- Alberts, B., Johnson, A., Lewis, J., Raff, M., Roberts, K., & Walter, P. (2002). Molecular biology of the cell. 5th ed. New York: Garland Science.
- Lehninger, A. L., Nelson, D. L., & Cox, M. M. (2005). Principles of biochemistry. 4th ed. New York: Worth Publishers.
- Stryer, L. (1995). Biochemistry. 4th ed. New York: W.H. Freeman and Company.
Cellular Respiration Q&A: Understanding the Process =====================================================
In our previous article, we explored the final stage of cellular respiration, oxidative phosphorylation, and how many molecules of ATP are produced at the end of this process. In this article, we will answer some frequently asked questions about cellular respiration and provide a deeper understanding of this complex process.
Q: What is cellular respiration?
A: Cellular respiration is the process by which cells generate energy from the food they consume. It involves the breakdown of glucose and other organic molecules to produce energy in the form of ATP (adenosine triphosphate).
Q: What are the three stages of cellular respiration?
A: The three stages of cellular respiration are:
- Glycolysis: The breakdown of glucose into pyruvate, which occurs in the cytosol of the cell.
- The citric acid cycle: The breakdown of pyruvate into acetyl-CoA, which occurs in the mitochondria.
- Oxidative phosphorylation: The production of ATP from the energy released in the citric acid cycle, which occurs in the mitochondria.
Q: What is the purpose of glycolysis?
A: The purpose of glycolysis is to break down glucose into pyruvate, which can then be used to produce energy in the form of ATP.
Q: What is the purpose of the citric acid cycle?
A: The purpose of the citric acid cycle is to break down pyruvate into acetyl-CoA, which can then be used to produce energy in the form of ATP.
Q: What is the purpose of oxidative phosphorylation?
A: The purpose of oxidative phosphorylation is to produce ATP from the energy released in the citric acid cycle.
Q: How many molecules of ATP are produced in glycolysis?
A: 2 molecules of ATP are produced in glycolysis.
Q: How many molecules of ATP are produced in the citric acid cycle?
A: 2 molecules of ATP are produced in the citric acid cycle.
Q: How many molecules of ATP are produced in oxidative phosphorylation?
A: 32 molecules of ATP are produced in oxidative phosphorylation.
Q: What is the total number of ATP molecules produced in cellular respiration?
A: The total number of ATP molecules produced in cellular respiration is 34.
Q: What is the energy yield of cellular respiration?
A: The energy yield of cellular respiration is 36-38 ATP molecules per glucose molecule.
Q: What is the purpose of the electron transport chain?
A: The purpose of the electron transport chain is to produce ATP from the energy released in the citric acid cycle.
Q: What is the role of NADH and FADH2 in cellular respiration?
A: NADH and FADH2 are electron carriers that play a crucial role in the production of ATP in cellular respiration.
Q: What is the difference between aerobic and anaerobic respiration?
A: Aerobic respiration occurs in the presence of oxygen and produces a higher yield of ATP, while anaerobic respiration occurs in the absence of oxygen and produces a lower yield of ATP.
Conclusion
In conclusion, cellular respiration is a complex process that involves the breakdown of glucose and other organic molecules to produce energy in the form of ATP. The three stages of cellular respiration are glycolysis, the citric acid cycle, and oxidative phosphorylation. The energy yield of cellular respiration is 36-38 ATP molecules per glucose molecule, and the total number of ATP molecules produced is 34.
References
- Alberts, B., Johnson, A., Lewis, J., Raff, M., Roberts, K., & Walter, P. (2002). Molecular biology of the cell. 5th ed. New York: Garland Science.
- Lehninger, A. L., Nelson, D. L., & Cox, M. M. (2005). Principles of biochemistry. 4th ed. New York: Worth Publishers.
- Stryer, L. (1995). Biochemistry. 4th ed. New York: W.H. Freeman and Company.