HNF 461 1st Edition Lecture 4 Outline of Last Lecture I Overview of Processes a TCA Cycle b Electron Transport Chain II PDH III TCA Cycle IV Electron Transport Chain V ATP Produced in Glycolysis TCA Cycle and PDH VI Malate Aspartate Shuttle VII Glycerol 3 Phosphate Shuttle VIII Brown Adipose Tissue Outline of Current Lecture I Hexosemonophosphate Shunt Pentose Phosphate Pathway a Oxidative Stage b Nonoxidative Stage II Glycogenesis a Glucose Phosphatase b Glycogen Synthase III Glycogen Branching IV Fatty Acid Synthesis Current Lecture HMP PPP Glycogenesis and Fatty Acid FA Synthesis 1 HMP PPP a Forms pentose phosphates building block for DNA RNA and NADPH for fatty acid synthesis b Two Stages i Oxidative Stage oxidizes glucose in 2 reactions 6 carbon sugar pentose Releases 1 CO2 and a total of 2 NADPH Not reversible ii Nonoxidative Stage sugar molecules exchange carbons between them to create new sugars with different arrangements but with the same total amount of carbons as the original structures ex 6 C and 4 C 3 C and 7 C Riboses are produced Reversible These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute 2 Glycogenesis Converts glucose to glycogen to store only occurs when glucose is abundant and in excess a Occurs in the liver and skeletal muscles Purpose is to help maintain blood glucose levels provides a cushion between eating and fasting periods Requires ATP b Liver glycogen is released into blood but muscle glycogen must stay in the muscle fibers i Glucose Phosphatase enzyme in liver that removes phosphate group from the glucose so that it can enter the blood c Process i GLUT 2 takes glucose out of the blood Glucokinase uses 1 ATP to start reaction ii Glucose UDP glucose Glycogenin protein provides the anchor for the 1st molecule then glucose molecules are added one at a time to form glycogen chain 1 Glycogen Synthase enzyme adds 1 glucose unit to glycogen chain active form desphosphorylated is stimulated by insulin inactive form phosphorylated 3 Glycogen Branching a Exposes more glucose residues at end of chains releases glucose at a faster rate b Saturates water so when chain is broken down it releases glucose and water to cells 4 Fatty Acid Synthesis lowest priority in energy metabolism a TCA Cycle Acetyl CoA Citrate b Citrate enters cytoplasm of mitochondria and is converted back to acetyl CoA catalyzed by citrate lyase Requires 1 ATP c Acetyl CoA malonyl CoA catalyzed by acetyl CoA carboxylase Requires 1 ATP d Two Domains on FA Chain i ACP Domain malonyl CoA attaches ii CE Domain acetyl CoA attaches e Process requires 2 NADPH to add two carbon to the chain f Process in NADPH dependent substrate reduces elongating FA chain in two steps g Body stores fats as triglycerides
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