This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Fatty acid and synthesis, Subject name: Biochemistry
Major source of NADPH for fatty acid synthesis is: 
Select and explain. 
A. HMP shunt, B. TCA cycle, C. Glycolysis, D. Uronic acid pathway
A: HMP shunt
Answer: A: HMP shunt 
Explanation: Reductases in fatty acid synthesis require NADPH as reducing power. Out of all the options, NADPH is produced by HMP shunt only. Insulin is lipogenic. It increases the production of enzymes of HMP shunt. Other minor pathways producing NADPH are:- Malic enzyme (NADP Malate Dehydrogenase) Cytoplasmic Isocitrate dehydrogenase Glutamate dehydrogenase