Final answer:
In Step 2 of the Krebs cycle, acetyl CoA goes into the cycle and two carbon dioxide molecules are released. Energy is stored in the form of 16 energy-carrying molecules, including NADH and FADH2, and one molecule of ATP is produced in each cycle.
Step-by-step explanation:
In the second step of the Krebs cycle, also known as the citric acid cycle, the reactant that 'goes in' is acetyl CoA. Acetyl CoA is derived from the breakdown of pyruvate, which is produced during glycolysis.
In this step, two carbon dioxide molecules are released and energy is stored in the form of 16 energy-carrying molecules, including NADH and FADH2.
One molecule of ATP is also produced in each cycle.
These energy carriers will be used in the final stage of cellular respiration, oxidative phosphorylation, to produce ATP.