This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Respiratory chain, Subject name: Biochemistry
NADPH is used in 
Select and explain. 
A. Fatty acid synthesis, B. Ketone synthesis, C. Glucogenesis, D. Glycolysis
A: Fatty acid synthesis
Answer: A: Fatty acid synthesis 
Explanation: FATTY ACID SYNTHESIS Materials Required for the SynthesisEnzymes-Fatty acid synthase, a multienzyme complex-Acetyl-CoA carboxylase, also a multienzyme complexCoenzymes and cofactors: Biotin, NADPH, Mn++CO2: Source of CO2 is bicarbonateATP: For energyFirst reaction (reduction): The keto-acyl group is reduced to hydroxy group (-OH) to form "b-OH butyryl-ACP" catalyzed by the enzyme "keto-acyl reductase". Second reaction (dehydration): A molecule of H2O is removed from "b-OH-butyryl-ACP" to form "a, bunsaturated butyryl-ACP" (also called crotonyl-ACP), catalyzed by the enzyme "b-OH-acyl dehydratase". Third reaction (reduction): The third and final reduction is catalyzed by "enoyl-reductase" using NADPH + H+, as a result, the double bond is saturated to form "butyryl-ACP" (4 carbon). All the above three reactions occur on "Pan-SH" of monomer II.Ref: MN Chatterjea Textbook of Medical Biochemistry, 8th Edition, Page no: 417