Question

1 a. NADP, FAD2, and NAD are all examples of co-enzymes. What role do these co-enzymes have in the processes of aerobic cellular respiration and photosynthesis?

1 b. Why are these molecules not classified as enzymes?

Answer 1

Ans:

Nicotinamide adenine di-nuclieotide phosphate is a nicotinic acid derivative that contains amide group and serves as co-enzyme in oxidation- reduction reaction like photosynthesis. In photosynthesis, NADP accepts electron to convert NADPH which is used as assimilatory power in Calvin cycle to produce carbohydrates and protects against the toxicity of reactive oxygen species.

FAD2 (flavin adenine dinucleotide) is a redox active coenzyme require for succinate dehydrogenase activity that oxidized succinate into fumarate and it is reduced to FADH2. The FADH2 converted back into FAD in oxidative phosphorylation and the free energy released in this conversion used in ATP production. It act as an electron carrier in cellular respiration.

NAD (Nicotinamide adenine di-nuclieotide) is a coenzyme used for pyruvate dehydrogenase, isocitrate dehydrogenase, $\alpha$ - ketoglutarate dehydrogenase and malate dehydrogenase activity and it is reduced to NADH.This NADH converted back into NAD in oxidative phosphorylation and the free energy released in this conversion used in ATP production. It act as an electron carrier in cellular respiration.

Coenzyme molecules not classified as enzymes because they are non-protein chemical substances that helps to catalyze enzyme reaction by acting as carriers of electrons or molecular groups.