Please answer this with the simplest answer , Please bolt the important answer **Question 12:**If acetyl-CoA containing radiolabeled carbons in the acetyl group was used to synthesize leucine, where would the radioactive carbons be found?---This question explores the metabolic pathway involving acetyl-CoA and its role in the biosynthesis of amino acids like leucine. It asks about the fate of radiolabeled carbons during this biochemical process, which is a crucial concept in understanding metabolic pathways and their intermediates in cellular biology.

Amino acids are biosynthesized from the intermediates of glycolysis, tricarboxylic acid cycle or the pentose phosphate/HMP shunt pathway. The Nitrogen atoms of the amino acids are donated by either glutamine or glutamate during the biosynthesis of all other amino acids. Among these different biosynthetic pathways, the amino acids alanine, valine, leucine and isoleucine are synthesized from pyruvate. Halfway through the synthesis pathway of leucine, acetyl Co.A enters. The biosynthetic pathway of leucine from the point of entry of acetyl Co.A is given below. The substrate of this reaction α-ketoisovalerate is derived from pyruvate (these initial steps are not shown ).The BLUE color represents the Acetyl group of acetyl Co.A. From the figure it is evident that the radiolabeled acetyl carbons are the alpha carbon and the C-terminal carboxylic acid carbon of leucine. (only consider the Carbon atoms in blue, the oxygen and hydrogen atoms that are in blue are also from acetyl group but these elements are not radiolabeled)