Physiology Exam Review

Physiology Exam Review - Physiology Exam Review: Metabolism...

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Physiology Exam Review: Metabolism – Glycolysis (cytosol): consumes 2 ATP but produces 4 ATP, for a NET gain of 2 ATP per glucose molecule o Glucose is phophoylated, NAD+ oxidized (loss of electrons) and in the end there are two molecules of pyruvic acid, 2 NADHs, 4 ATPs (but only 2 in NET gain) o Split by enzyme phosphofructokinase (uses ATP) o Most cells use the 2 NADHs to make 4 ATPs, but Hepatocytes, kidney cells, and cardiac muscle fibers can make up to 6 ATPs from the 2 NADHs o With out oxygen, pyruvic acid will continue to produce NAD+ by means of the anaerobic pathway to produce 2lactic acid and 2NADH o With oxygen pyruvic acid converted to acetyl CoA Krebs Cycle (Matrix Mitochondira): for each Acetyl CoA: 3 NADH (= 9ATP), 1 FADH2 (= 2 ATP), and 1 ATP are produced. Since for one glucose molecule go through Krebs 2 times we get 24 ATP o Also produce NADH before entering Krebs (twice) so that’s another 6ATP, so really Krebs gives us 30 ATP. o Main enzyme of Krebs cycle is Pyruvate Dehydrogenase. Regulated by NADH + H ratio to NAD ratio o SLOW, HIGH ATP, OXYGEN dependent Electron Transport Chain: o Embedded in mitochondria membrane, but ATP synthase (driven by H+ ions) happens in the matrix When glucose not needed to be used to make ATP it is stored in our body by the hepatocytes and skeletal muscle cells to carry out glycogenesis (synthesis of glycogen). This process stimulated by insulin Glucose From FATS and PROTEINS: Gluconeogenesis – conversion of noncarbs into glucose (stimulated by cortisol and glucagon) FAT into GLUCOSE: Lipolysis – split of triglycerol into glycerol and fatty acid) o If ATP is high in the body, glyceraldehydes converted into glucose (first glyceraldehydes 3-phosphate then glucose 6-phosphate), if its low glyceraldehydes enters pathway as pyruvic acid o Energy process from fat is called Beta-Oxidation Glycerol into glucose Fatty acid into beta-oxidation – breaking down the fatty acid chain into CoA-C-C makes NADH and FADH Lipid metabolism for 16chain fatty acid makes 131 ATP o Carnatine-Polmuteal Tranferase (CPT) – move fatty acid into mitochondria Ketone Bodies – formed in liver as a result of Free Fatty Acids (heart, brain, and cortex of kidney use acetoacetate to make glucose when cannot get it else where PROTEIN to GLUCOSE
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o Protein has nitrogen which must be removed before can get energy from it Deanimation – occurs in hepatocytes and produces ammonia Once remove the ammonia we are left with Pyruvic acid and can be made into glucose in the liver Glucose-Alanine: 2 alanine from the muscle into blood stream can be taken up by the liver and made into glucose (also with Glutamine and Alanine) Other AAs will be able to enter somewhere in the krebs cycle Extra protein goes into the protein pool, but might be stored as triglycerides if there is enough protein in the body IMPORTANT PLAYERS IN METABOLISM: o Glucose-6-phosphate, pyruvic acid, acetyl CoA
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This note was uploaded on 03/20/2008 for the course EXSS 276 taught by Professor Hacnkey during the Spring '08 term at UNC.

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Physiology Exam Review - Physiology Exam Review: Metabolism...

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