Final answer:
In the process of glycolysis, glucose is split into two molecules of pyruvate, after the initial phosphorylation step that consumes two ATP molecules. This results in a net gain of two ATP molecules for the cell.
Step-by-step explanation:
In the second main event of glycolysis, a molecule of glucose is split into two three-carbon molecules known as pyruvate. The process begins with the investment of energy through the consumption of two ATP molecules which phosphorylate the glucose molecule, transforming it into fructose-1,6 biphosphate. This is then split during the cleavage stage into two molecules of glyceraldehyde 3-phosphate. Further reactions convert each of these molecules into pyruvate, producing a total of four ATP and two NADH, resulting in a net gain of two ATP molecules for the cell.
Thus, the complete sentence for the student's question would be: In the second main event of glycolysis, glucose is split into two molecules of pyruvate.