Question

Reaction I is the first committed step in fatty acid synthesis, and reaction II is the first step in the conversion of pyruvate to glucose in gluconeogenesis. Both acetyl-CoA and pyruvate are carboxylated at the expense of ATP. What is the chemical logic behind this energy expenditure in both cases? For full marks, provide your answer with reaction schemes and electron pushing arrows.

Answer 1

DATE: / 20 PAGE NO 1 2Uce Gluconeogenesis begins in the mitochondre in which pyruvate i converted into your Phosphoenol byruvate į feconed formed from the the byruvate Oxalo acetate į formed by the cauboxylation of byruvate this reaction require one molecus of ATP and is catalysed by pyruvate Carhoryland This enzyme į stimulated by high level of @cetyl-COA Oxaloacetate ů reduced to malate using NATH Malate ů oxidize to oxaloacetate using NADA in the custolt a Oxaloacetate į decarboxylate and then phosphorylate to foom Phosphoenolbyruvate A molecule of GTP Å bydrolysed to GDP and PEPCK enzyme Ý used during this RX3 Final step of gluconeogenesis ý formation of glucose from phosphoenolsyruvate. HCO3 + ATP Pyruvate - - Pyruvate - → oxaloacetate . ADP+Pivo ALT Alanine (Pyruvate comboxylase] NADH+H NAST Kytoselic Malate malate oxaloacetate dehyduogenase NADT (malate de NADH+HT phosphoenolby ourate - GTP cytoselic u Per carbony kinase GDP + con Glucose

DATE: / PAGE NO Po 2 fatty acid synthesis start with the carbonylate of acetyl-CoA to malonye con. This irreversible reaction is the committed steh in fatty acid synthesis. process involve conversion of acety-CoA into malonge -Con this reaction ý catalysed by acetye - CoR coreboxylase. Cacc Then malonyl-con convent to a malonye- ACP Condensation of malenye - Acp with another molecule of acetyl-CoA to form ß- ketoacyl-Ace And erne Catalysed by B - ketoacyl - ACP synthase Reduction of B-keto acyl-Ace into B- hydroxyacue - Ace 64 B-oxoacyl-Ace deductase and its debydration by B-hydroxy acyl - ACE dehydratase to enoye - Aco Reduction of enoye - ACP to butyryl Ace by eneye ALP Meductase which then convents to acce- ACP which finally give octanoye - ACP. octanoye - ACP then convent to Lipoic acid - ACP COA Acetye-con AC malonye-CoA RC malon LACO Log+ATP A 3-hydroxy KARI Kas_Acetyl coa acye-acpite 3-keto acyl-ALPE HTD 4 Hgo NAPP NADPH +HT N APPH+H" NADPT Enoyl-ACP Alge-ALP - ► octancyl-ACP ETR Lipoic acid.