Question

What is the difference between NADH2 and NADPH2

• A. NADH2 has an extra phosphate group on the ribose sugar attached to adenine, unlike NADPH2.
• B. NADPH2 is primarily used in cellular respiration for ATP production, while NADH2 is mainly used in reductive biosynthesis.
• C. NADPH2 has an extra phosphate group on the ribose sugar attached to adenine, unlike NADH2.
• D. NADH2 is involved in photosynthesis, while NADPH2 is involved in cellular respiration.

Answer 1

Answer: (C)

NADPH2 has an extra phosphate group on the ribose sugar attached to adenine, unlike NADH2.

Answer 2

The primary structural difference between NADH (Nicotinamide Adenine Dinucleotide) and NADPH (Nicotinamide Adenine Dinucleotide Phosphate) lies in the presence of an additional phosphate group in NADPH. This phosphate group is attached to the 2'-hydroxyl group of the ribose sugar that is linked to adenine. Consequently, their reduced forms, NADH2 and NADPH2 (commonly referred to as NADH and NADPH), also differ in this regard.

Functionally, NADH is predominantly involved in cellular respiration, acting as a reducing agent in pathways like glycolysis, the Krebs cycle, and the electron transport chain to generate ATP. In contrast, NADPH is primarily utilized in reductive biosynthesis (anabolic processes such as fatty acid and steroid synthesis), photosynthesis (specifically in the Calvin cycle), and antioxidant defense mechanisms.