What process converts glucose into pyruvate, producing ATP?

The process that converts glucose into pyruvate, while producing ATP, is glycolysis. This pathway occurs in the cytoplasm of the cell and involves a series of enzymatic reactions that break down one molecule of glucose (a six-carbon sugar) into two molecules of pyruvate (each with three carbons).

During glycolysis, the process begins with energy investment where two ATP molecules are consumed to phosphorylate glucose, making it more chemically reactive. As the pathway progresses, glucose is split and further processed, resulting in the production of four ATP molecules through substrate-level phosphorylation, leading to a net gain of two ATP molecules, since two were initially used. Additionally, glycolysis also produces two molecules of NADH, which can be used in later stages of cellular respiration to generate more ATP in the presence of oxygen.

Glycolysis is the first step in both aerobic and anaerobic respiration, making it an essential mechanism for cellular energy production. The subsequent metabolic pathways, such as the citric acid cycle and oxidative phosphorylation, further process the pyruvate generated to extract more energy, but the direct conversion of glucose to pyruvate with ATP production occurs solely during glycolysis.