Which process involves the breakdown of glucose under anaerobic conditions to produce lactic acid and can occur in muscle cells and certain bacteria?

Which process involves the breakdown of glucose under anaerobic conditions to produce lactic acid and can occur in muscle cells and certain bacteria?

• A. Fermentation
• B. Chemoautotrophy
• C. Nonsense mutations
• D. Lactic acid fermentation

Answer: (D)

Lactic acid fermentation is the anaerobic breakdown of glucose to lactate, a process that can occur in muscle cells and some bacteria. In the absence of oxygen, glycolysis still converts glucose to pyruvate and generates a small amount of ATP. The pyruvate is then reduced to lactate by lactate dehydrogenase, using electrons from NADH and regenerating NAD+. This regeneration of NAD+ allows glycolysis to continue, providing ATP without oxygen. The end product is lactate, hence the name lactic acid fermentation. Fermentation in general refers to this NAD+ regeneration under anaerobic conditions, but the specific pathway described here yields lactate rather than the ethanol and CO2 produced in alcoholic fermentation. The other options refer to unrelated concepts: chemoautotrophy is energy from inorganic compounds, and nonsense mutations are genetic changes that disrupt protein coding.

Lactic acid fermentation is the anaerobic breakdown of glucose to lactate, a process that can occur in muscle cells and some bacteria. In the absence of oxygen, glycolysis still converts glucose to pyruvate and generates a small amount of ATP. The pyruvate is then reduced to lactate by lactate dehydrogenase, using electrons from NADH and regenerating NAD+. This regeneration of NAD+ allows glycolysis to continue, providing ATP without oxygen. The end product is lactate, hence the name lactic acid fermentation. Fermentation in general refers to this NAD+ regeneration under anaerobic conditions, but the specific pathway described here yields lactate rather than the ethanol and CO2 produced in alcoholic fermentation. The other options refer to unrelated concepts: chemoautotrophy is energy from inorganic compounds, and nonsense mutations are genetic changes that disrupt protein coding.