glycolysis

net reaction per molecule of glucose

Glucose + 2 ADP + 2 PO4 → 2 pyruvate + 2 ATP + 4 H+

Not a very efficient reaction... needs 2 ATP to kick things off

conversion of pyruvate needed for Krebs cycle substrate

2 pyruvate + 2 CoA → 2 acetyl CoA + 2 CO2 + 4H

acetyl CoA then goes to start the Krebs cycle.