L08b - NATS1610-fw1718 - UPDATED - Mitochondria and Cell Metabolism (1).pdf

B figure shows only one of the 2 pyruvates from

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B. Figure shows only ONE of the 2 pyruvates from glycolysis
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Step 3: The Electron Transport Chain and ATP Synthesis 29
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How Cells Make ATP: STEP 3 (occurs INSIDE mitochondria) The ELECTRON TRANSPORT CHAIN n A “series of protein- complexes embedded within the inner mitochondrial membrane” (not shown in this figure) n Requires oxygen n Forms 32 ATP molecules (per one glucose) General mechanism n NADH & FADH 2 “carry” hydrogens & electrons n BRING them to the electron transport chain in INNER mitochondrial membrane n H + gradient formed ACROSS the inner membrane n Formation of large amounts of ATP by ATP synthase (enzyme) 30 Matrix Intermembrane compartment Image from page A-7, (Appendix 1) - from Starr and McMillan, Human Biology , 10ed, Brooks Cole ATP Synthase
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31 NADH and FADH 2 deliver electrons to electron transfer chains (protein-complexes ) in the inner mitochondrial membrane. 1 1 Electron Transport Chain intermembrane space outer membrane cytoplasm matrix inner membrane Electron-flow through the chains causes hydrogen ions (H + ) to be pumped from the matrix to the intermembrane space. 2 2 The activity of the electron transfer chains causes a hydrogen ion gradient to form across the inner mitochondrial membrane (more H + in intermembrane space) . 3 3 Hydrogen ion flow-back into the matrix through ATP synthases drives the formation of ATP from ADP and phosphate (Pi). 4 4 Oxygen (O 2 ) accepts electrons and hydrogen ions at the end of mitochondrial electron transfer chains, so water forms . 5 5 Image from page A-7, (Appendix 1) - from Starr and McMillan, Human Biology , 10ed, Brooks Cole The BIG PICTURE - Steps of the Electron Transport Chain
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Let’s explore the Mitochondria’s Hydrogen Ion Concentration Gradient 32
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The HYDROGEN ION GRADIENT “drives” the formation of ATP GRADIENTS exist where there is a higher concentration of a material in one compartment compared to it’s concentration in a neighbouring compartment n There’s “potential energy” in gradients – to "drive” chemical reactions n Because materials want to move from an area where they’re in a higher concentration to an area where they are in a lower concentration i.e., ATP Synthase is “driven” by a H+ gradient n 3 hydrogen ions from the mitochondrial intermembrane space enter ATP synthase n these then exit into the mitochondrial matrix space n resulting in the formation of an ATP molecule n *** Animation of Gradients and ATP Synthase n n *** The Hydrogen Ion gradient (aka proton gradient) is maintained through the actions of the ELECTRON TRANSPORT CHAIN (a series of enzymes) n Image from -
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34 intermembrane space cytoplasm outer membrane inner membrane matrix First step Second step Third step Glycolysis glucose Krebs Cycle Electron Transfer Phosphorylation oxygen 2 CO 2 4 CO 2 2 2 NADH 2 NADH 2 NADH 6 NADH 2 FADH 2 2 2 NAD + (2 net ATP) 4 2 pyruvate 2 acetyl-CoA 32 Image from page A - 8, (Appendix 1) - from Starr and McMillan, Human Biology , 10ed, Brooks Cole ANAEROBIC RESPIRATION AEROBIC RESPIRATION SUMMARY : Cellular Respiration
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Other FOOD molecules also provide energy for making ATP (their Breakdown Products enter into the Cellular Respiration process at various steps)
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