Final answer:
Glycolysis is the first step in the breakdown of glucose, resulting in the formation of ATP. It involves splitting a six-carbon glucose molecule into two three-carbon pyruvate molecules.
Step-by-step explanation:
Glycolysis is the first step in the breakdown of glucose, resulting in the formation of ATP, which is produced by substrate-level phosphorylation. During glycolysis, a single six-carbon glucose molecule is split into two molecules of a three-carbon sugar called pyruvate. This process occurs in the cytoplasm of the cell and does not require oxygen.