What step in aerobic respiration comes after glycolysis?

After glycolysis, the next step in aerobic respiration is the citric acid cycle, also known as the Krebs cycle. Glycolysis, which occurs in the cytoplasm, breaks down glucose into pyruvate, producing a small amount of ATP and NADH in the process. The pyruvate generated then moves into the mitochondria where it undergoes further processing.

In aerobic conditions, pyruvate is converted into acetyl-CoA, which serves as a key input for the citric acid cycle. The cycle takes place in the mitochondrial matrix and is crucial for the extraction of high-energy electrons from the breakdown of organic molecules. It leads to the production of additional NADH and FADH2, which are essential for the subsequent electron transport chain, where most of the ATP is generated.

Fermentation occurs in anaerobic conditions as an alternative pathway when oxygen is not available, while gluconeogenesis is a metabolic pathway that generates glucose from non-carbohydrate precursors. The electron transport chain is indeed another step following the citric acid cycle but it occurs after the citric acid cycle has processed the products of glycolysis. Therefore, the citric acid cycle is the correct step that directly follows glycolysis in the sequence of aerobic respiration