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▪Substrate level phosphorylation:forms ATP, b/c phosphate group transferred from ADP. ▪At pyruvate: oIf aerobic:goes to Krebs→broken into CO2oIf anaerobic: makes lactate ▪Lactate is made by:glucose + 2 ADP + 2 Pi →2 Lactate + 2 ATP + 2 H2O oIn which 2 hydrogens transferred from NADH + H+ to pyruvate, NAD+ regenerates. ▪Then lactate will either go to the blood function in heart and tissues and regenerate as pyruvate or goes to liver to form glucose. ▪If it is going to Krebs:NADH + H+ will transfer to O2 during oxidative phosphorylation regenerating NAD+ and producing H20. ▪The amount of ATPproduced by glycolysis (lactate) is much smallerthan the ones that go into Krebs and oxidative phosphorylation. ▪Also, carbs such as fructose, galactose can perform glycolysis. Krebs Cycle ▪Involved in nutrient catabolism and ATP production ▪Produces co2, hydrogen and small amounts of ATP. ▪Molecule entering is acetyl CoA–comes from pyruvate or breakdown of fatty acids/ AA. ▪Enters the mitochondria from the cytosol.▪Krebs only does aerobic because O.P. necessary for regeneration of hydrogen free coenzymes. Entering Krebs: Acetyl coA Location: Inner mitochondrial matrix ATP production: 1 GTP, can convert to ATP, only aerobic, (GTP + ADP <--> GDP + ATP) Coenzyme prod: 3 NADH + 2 H+ 2 FADH2 Final Products: 2 CO2 for each acetyl coA
17 Net Reaction: Acetyl coA + 3 NAD + FAD + GDP + Pi + 2 H2O ---> 2 CO2 + CoA + 3 NADH + 3 H+ + FADH2 + GTPOxidative Phosphorylation ▪Energy transfer from ATP is derived from energy released when H++ O2= H2O. ▪From Krebs we have 3 NADH + 2 H++ 2 FADH—these hydrogens are pumped in system. ▪Proteins either—transfer H+ to O2or will couple E release to synthesize ATP. ▪These proteins will combine with cytochromes (proteins that have Fe and Cu factors) to transfer 2e- to ETC. ▪These 2e- are transferred to others in the chain to/from cytochromes until they are officially transferred to O ▪Energy is also released during the process—cytochromes use this to pump H+ into intermembrane space. oThe hydrogen ions flow down concentration gradient across inner mitochondrial membrane through a channel by ATP synthase. ATP synthase takes this energy and synthesizes ATP from ADP + Pi. Maximum of 2-3 ATP produced per 1 e- donated. oChemiosmosis:process in which the inner mitochondrial matrix channel allows for H+ ions to flow back to matrix side. ▪Finally, H++ O2= H2O →Regenerates 2 H+ →used for glycolysis, Krebs & fatty acids. ▪Regeneration of the H+free form of the coenzyme is aerobic Carbohydrate Metabolism ▪Found in Glycolysis, Krebs and O.P. ▪Amount of E released is 686 kcal/mol and 40% of this energy is transferred to ATP. ▪2 net ATP →phosphorylation in Glycolysis ▪2 net ATP →Krebs ▪34 ATP →Oxidative phosphorylation from generation of ATP.