Answer:
Glycolysis:
Glycolysis is the primary step of cellular respiration in which glucose molecule is broken down to pyruvate in a set of reaction and produce energy. It generates two molecules of pyruvate, ATP, NADH and water. The process takes place in aerobic as well as anaerobic conditions in the cytosol of the cell cytoplasm.
Significance: generate pyruvate for the next stage, pyruvate oxidation, and release four ATP molecules while spends two ATP molecules in glycolysis, for a net gain of two ATP molecules.