What function does lactate dehydrogenase serve in anaerobic metabolism?

What function does lactate dehydrogenase serve in anaerobic metabolism?

• A. Converts glucose to pyruvate
• B. Regenerates NAD+
• C. Produces ATP directly
• D. Facilitates the Krebs cycle

Answer: (B)

Lactate dehydrogenase plays a crucial role in anaerobic metabolism by regenerating NAD+. In the absence of oxygen, cells rely on anaerobic glycolysis to produce energy. During this process, glucose is broken down into pyruvate, which is then converted into lactate when oxygen levels are low. This conversion by lactate dehydrogenase is essential because glycolysis requires NAD+ to continue. In the process of converting pyruvate to lactate, NADH, which is generated during glycolysis, is oxidized back to NAD+. The regeneration of NAD+ allows glycolysis to continue, ensuring a limited supply of ATP can be produced even in anaerobic conditions. Without the action of lactate dehydrogenase and the consequent replenishment of NAD+, the glycolytic pathway would stall, significantly impairing the cell's ability to produce energy under anaerobic conditions. The other choices do not adequately represent the role of lactate dehydrogenase in this context; while glucose is converted to pyruvate in glycolysis, that process is separate and occurs before the lactate dehydrogenase action. ATP production does occur during glycolysis but is not a direct function of lactate dehydrogenase. Lastly,

Lactate dehydrogenase plays a crucial role in anaerobic metabolism by regenerating NAD+. In the absence of oxygen, cells rely on anaerobic glycolysis to produce energy. During this process, glucose is broken down into pyruvate, which is then converted into lactate when oxygen levels are low.

This conversion by lactate dehydrogenase is essential because glycolysis requires NAD+ to continue. In the process of converting pyruvate to lactate, NADH, which is generated during glycolysis, is oxidized back to NAD+. The regeneration of NAD+ allows glycolysis to continue, ensuring a limited supply of ATP can be produced even in anaerobic conditions. Without the action of lactate dehydrogenase and the consequent replenishment of NAD+, the glycolytic pathway would stall, significantly impairing the cell's ability to produce energy under anaerobic conditions.

The other choices do not adequately represent the role of lactate dehydrogenase in this context; while glucose is converted to pyruvate in glycolysis, that process is separate and occurs before the lactate dehydrogenase action. ATP production does occur during glycolysis but is not a direct function of lactate dehydrogenase. Lastly,