<prompt> Acetyl co-A can he directly converted to all except:GlucoseFatty acidsCholesterolKetone bodies  <response>: Ans. a. Glucose Ref: Harper 29e p123, 164, 187-189; Lippincott 4e p266, 111-112, 220, 96, 119, 192, 195-196 Lehninger 5e p616-617. 695. 557Acetyl CoA is not a substrate for gluconeogenesis and cannot be converted back to glucose.Acetyl coenzyme A arises from pyruvate the end product ofaerobic glycolysis by irreversible oxidative decarboxylation catalyzed by pyruvate dehydrogenase PDH complex.Acetyl CoA is not a substrate for gluconeogenesis and cannot be converted back to glucose. This is because acetyl CoA cannot be converted back to pyruvate since its carbon backbone is lost in citric acid cycle as CO2.Acetyl CoA is used in oxidative phosphorylation in TCA cycle for energy production; in acetylation reaction coenzyme pantothenic acid for detoxification and acetyl choline formation. It is also used in cholesterol synthesis, steroidogenesis steroid hormone and vitamin D synthesis, lipogenesis fatty acid synthesis and elongation, synthesis of ether lipids like plasmalogens and PAF and ketogenesis ketone body-formation. Acetyl CoA is a precursor or starting material and substrate for enzymes for synthesis of cholesterol and ketone bodies substrate for HfG CoA synthetase and fatty acid synthesis substrate for fatty acid synthase, acetyl CoA carboxylase or malonyl CoA synthetase and malonyl transaeetylase. 