Question

In anaerobic conditions, what happens to pyruvate in human skeletal muscle, and why is anaerobic respiration advantageous to muscle cells?

A) Pyruvate is converted into acetyl-CoA, which is more efficient. Anaerobic respiration provides more ATP.
B) Pyruvate is converted into lactic acid, reducing the risk of muscle fatigue. Anaerobic respiration allows for quick energy production.
C) Pyruvate is converted into carbon dioxide and water, eliminating the need for oxygen. Anaerobic respiration is more sustainable for muscle cells.
D) Pyruvate is converted into glucose, allowing for long-term energy storage. Anaerobic respiration is essential for muscle growth.

Answer 1

In anaerobic conditions, pyruvate is converted into lactic acid. Anaerobic respiration is advantageous to muscle cells because it allows for rapid ATP production when oxygen is limited.

Step-by-step explanation:

When oxygen is limited or absent, pyruvate enters an anaerobic pathway called fermentation. In these reactions, pyruvate can be converted into lactic acid. In addition to generating an additional ATP, this pathway serves to keep the pyruvate concentration low so glycolysis continues, and it oxidizes NADH into the NAD* needed by glycolysis. Anaerobic respiration occurs in most cells of the body when oxygen is limited or mitochondria are absent or nonfunctional. This is an effective pathway of ATP production for short periods of time, ranging from seconds to a few minutes. The lactic acid produced diffuses into the plasma and is carried to the liver, where it is converted back into pyruvate or glucose via the Cori cycle. Similarly, when a person exercises, muscles use ATP faster than oxygen can be delivered to them. They depend on glycolysis and lactic acid production for rapid ATP production.