Before the pyruvate produced in glycolysis can enter the Krebs cycle, it is first oxidized, leading to the production of 1 CO2, 1 NADH, and 1 molecule of acetyl-CoA per pyruvate (see figure below or poster on lab wall).

A digram showing the preparatory step that pyruvate undergoes prior to entering the Krebs cycle. 2 molecules of pyruvate, which each consist of 3 carbon atoms, are turned into 2 molecules of acetyl-CoA, which each consist of a 2 carbon acetyl group and coenzyme A. In the process of this transformation, 2 NA Dplus molecules are reduced to 2 NADH molecules. The 2 carbon atoms that are lost from pyruvate, with each pyruvate losing one carbon atom, are released as 2 molecules of carbon dioxide. Acetyl-CoA enters the Krebs cycle.

Krebs cycle preparation: x2 indicates that two pyruvate molecules are produced for each glucose molecule.