Which metabolic pathway is common to both fermentation and cellular respiration of a glucose molecule? a. the citric acid cycle b. the electron transport chain c. glycolysis d. reduction of pyruvate to lactate

Verified step by step guidance

1. Identify the metabolic pathways involved in both fermentation and cellular respiration. Fermentation is an anaerobic process, while cellular respiration can be aerobic.
2. Recall that glycolysis is the initial step in the breakdown of glucose and occurs in both aerobic and anaerobic conditions.
3. Understand that the citric acid cycle and the electron transport chain are parts of aerobic respiration and do not occur in anaerobic fermentation.
4. Recognize that the reduction of pyruvate to lactate specifically occurs during lactic acid fermentation, not in all types of fermentation or in aerobic respiration.
5. Conclude that glycolysis is the only pathway among the options that is common to both fermentation and cellular respiration.

Key Concepts

Glycolysis

Glycolysis is the metabolic pathway that breaks down glucose into pyruvate, producing a small amount of ATP and NADH in the process. It occurs in the cytoplasm and is the first step in both fermentation and cellular respiration, making it a universal pathway for energy extraction from glucose.

Fermentation

Fermentation is an anaerobic process that allows cells to generate energy without oxygen. It follows glycolysis when oxygen is scarce, converting pyruvate into various end products, such as lactic acid or ethanol, while regenerating NAD+ to sustain glycolysis.

Cellular Respiration

Cellular respiration is an aerobic process that fully oxidizes glucose to produce ATP, carbon dioxide, and water. It includes glycolysis, the citric acid cycle, and the electron transport chain, allowing for a more efficient energy yield compared to fermentation.