NANP Board Practice Exam

Which molecule is key for the synthesis of fatty acids in the Pentose Phosphate Pathway?

1. NADH

2. NADPH

3. Ribose 5-phosphate

4. ATP

The correct answer is: NADPH

The correct answer is indeed NADPH. This molecule plays a critical role in anabolic processes, including the synthesis of fatty acids. In the Pentose Phosphate Pathway, one of its main functions is to generate NADPH, which serves as a reducing agent in various biosynthetic reactions. NADPH provides the necessary reducing power for the conversion of acetyl-CoA into fatty acids. Specifically, it donates electrons in the reduction reactions, which are vital for the elongation of the fatty acid chain during synthesis. This process is crucial for producing the lipids needed for cellular membranes, energy storage, and signaling molecules. In contrast, while ATP is important for energy transfer in the body and NADH is used primarily in catabolic reactions to produce energy, they do not directly contribute to fatty acid synthesis the way NADPH does. Ribose 5-phosphate, on the other hand, is involved in nucleotide synthesis rather than fatty acid metabolism. Therefore, NADPH is uniquely positioned as the key molecule required for fatty acid synthesis in the context of the Pentose Phosphate Pathway.