Answer:
NAD is reduced
Step-by-step explanation:
Glycolysis is the first step in the breakdown of glucose in order to generate energy for cellular metabolism. Glycolysis helps to convert glucose into pyruvate and hydrogen ion.
In redox reaction, oxidation is the removal of hydrogen and reduction is the addition of oxygen. In the process of glycolysis, the NAD is reduced to form NADH and H.
If NAD is not present, glycolysis will not be able to continue. During aerobic respiration, the NADH formed in glycolysis will be oxidized to reform NAD+ for use in glycolysis again.