Question

What happens during the process of respiration when ATP is still needed, but oxygen is not available to accept electrons and hydrogen ions in the electron transport chain?

A. Glycolysis stops
B. ATP production increases
C. Lactic acid fermentation occurs
D. Krebs cycle accelerates

Answer 1

When oxygen is not available, fermentation occurs, converting pyruvate into lactic acid and allowing glycolysis to continue.

Step-by-step explanation:

In the absence of oxygen, when ATP is still needed, pyruvate enters an anaerobic pathway called fermentation. In this process, pyruvate is converted into lactic acid, which serves as the final electron acceptor.

This allows glycolysis to continue, generating an additional ATP and regenerating NAD+ needed for glycolysis.