Consider the role of the coenzyme NAD in glucose oxidation. In the process of glycolysis the formation of pyruvate involves the reduction of the coenzyme NAD to NAD.2H.

(a) Which other stages of glucose oxidation produce molecules of the reduced coenzyme, NAD.2H?

(b) Explain what happens to NAD.2H produced during glycolysis in:

i) an animal cell respiring aerobically

ii) an animal cell respiring anaerobically

(c) The oxidation of NAD.2H is an energy-releasing process. Name the energy-requiring process it is coupled to and why this is important for the cell.