Question

Which of the following statements is most correct?

A. NAD/NADH are involved in catabolic reactions.
B. In plants the major source of NADH is from ferredoxin formed from the high energy electrons generated by Photosystem II.
C. Large molecules are built using catabolic reactions.
D. NADP is not found in animal cells.

Answer 1

The statement 'NAD/NADH are involved in catabolic reactions' is the most correct. In these reactions, NADH stores energy from the breakdown of molecules, which is later used to produce ATP.

Step-by-step explanation:

NAD/NADH are involved in catabolic reactions. NAD+ (oxidized form) and NADH (reduced form) play crucial roles in energy metabolism.

Catabolic reactions break down large organic molecules into smaller ones, releasing energy that can be harnessed to produce ATP, the energy currency of cells.

While involved in multiple stages of metabolism, NADH is particularly prominent in the citric acid cycle, where it gains electrons to store energy and then donates them during the electron transport chain to help generate ATP.

Conversely, NADP+/NADPH are involved primarily in anabolic reactions and photosynthesis; for example, NADPH is produced in the light reactions of photosynthesis and used during the Calvin cycle to assimilate carbon dioxide into organic molecules.