Questions: In the absence of oxygen, some organisms produce ethanol (alcohol) and ATP from pyruvate and NADH. What is the name of this anaerobic pathway? A. Electron Transport System B. Glycolysis C. Fermentation D. Krebs Cycle

The answer is C: Fermentation.

Explanation for each option:

A. Electron Transport System: This is a part of aerobic respiration where electrons are transferred through a series of complexes to produce ATP. It requires oxygen, so it is not the correct answer for an anaerobic process.

B. Glycolysis: This is the process of breaking down glucose into pyruvate, producing ATP and NADH in the process. While glycolysis occurs in both aerobic and anaerobic conditions, it does not specifically refer to the conversion of pyruvate to ethanol and ATP in the absence of oxygen.

C. Fermentation: This is the correct answer. Fermentation is an anaerobic process where organisms convert pyruvate into ethanol and carbon dioxide, regenerating NAD+ from NADH, allowing glycolysis to continue producing ATP in the absence of oxygen.

D. Krebs Cycle: Also known as the Citric Acid Cycle, this is a part of aerobic respiration that occurs in the mitochondria and requires oxygen. It is not involved in anaerobic processes like fermentation.

In summary, the anaerobic pathway where organisms produce ethanol and ATP from pyruvate and NADH is called fermentation.