Energy Generation In The Body Lesson 7 PDF

ENERGY GENERATION IN THE BODY Lesson 7 Energy generation in the body Concept and functional role of biological oxidation. Respiratory chain and ATP synthesis. Role of the CAC in the generation of energy ELECTRON TRANSPORT CHAIN Electron-transfer chain: sequence...

ENERGY GENERATION IN THE BODY Lesson 7 Energy generation in the body Concept and functional role of biological oxidation. Respiratory chain and ATP synthesis. Role of the CAC in the generation of energy ELECTRON TRANSPORT CHAIN Electron-transfer chain: sequence of electron-carrying proteins that transfer electrons from substrates (NADH and FADH2) to molecular oxygen in aerobic cells. AH2 OXIDATION NAD+ or FAD 1 REACTIONS. ELECTRON TRANSPORT CHAIN NADH + H+ ½ O2 + 2H+ CATABOLISM or FADH2 H2O A 2 ENERGY Functions: Regenerate the oxidized forms of the coenzymes to continue the oxidation reaction (catabolism) Enery release through the electron transport ELECTRON TRANSPORT CHAIN Location  Inner mitochondrial membrane Components: 4 complexes  I, II III and IV 2 carriers  Coenzyme Q and cytochrome C Complex I, III and IV pump protons to the intermembrane space at the same time as the electrons pass through them. Complexes are located on increasing affinity to electrons The electrons are transported from NADH and FADH2 (electron donors) to oxygen (electron acceptor). ELECTRON TRANSPORT CHAIN Respiratory complexes: I, II, III, IV Electron donors: NADH and FADH2 Electron acceptor: Oxygen Free transporters: Coenzyme Q, Electron affinity cytochrome C ELECTRON TRANSPORT CHAIN AND OXIDATIVE PHOSPHORYLATION Oxidative phosphorylation: The enzymatic (by ATP synthase) phosphorylation of ADP to ATP coupled to electron transfer from a substrate to molecular oxygen. Both processes are coupled  ATP synthase is also called Complex V. ENERGY RESPIRATORY CHAIN ADP + Pi ATP ATP SYNTHASE (endergonic process) ELECTRON TRANSPORT CHAIN AND OXIDATIVE PHOSPHORYLATION CHEMIOSMOTIC THEORY (MITCHELL) Theory that explains how the electron transport chain and oxidative phosphorylation are coupled Transmembrane differences in proton concentration are the reservoir for oxidative phosphorylation 2 steps are involved: Proton pump  Re-entry of the protons through ATP synthase Chemiosmotic theory: The theory that energy derived from electron transfer reactions is temporarily stored as a transmembrane difference in charge and pH, which subsequently drives the formation of ATP in oxidative phosphorylation CHEMIOSMOTIC THEORY (MITCHELL) PROTON PUMP Electron flow is accompanied by proton transfer across the inner membrane The inner mitochondrial membrane is impermeable to protons Proton-motive force  electrochemical energy inherent in the difference in proton concentration and the separation of charge across Proton -motive force the inner mitochondrial membrane Chemical potential Electrical potential (different pH) (different charge) CHEMIOSMOTIC THEORY (MITCHELL) RE-ENTRY OF THE PROTONS THROUGH ATP SYNTHASE Protons flow passively back into the matrix through a proton pore in ATP synthase Thermodynamically favorable process exergonic Released energy is used for ATP synthase for the synthesis of ATP. Proton -motive force ATP synthesis 4 protons are required to driven by proton- synthesize 1 ATP Chemical potential Electrical potential motive force (different pH) (different charge) THE CITRIC ACID CYCLE Multistep catalytic process that converts acetyl-CoA derived from carbohydrates, fatty acids and amino acids to CO2, and produces NADH, FADH2, and ATP Also called the tricarboxylic acid (TCA) cycle or the Krebs cycle GENERAL FEATURES: Location Mitochondrial matrix Functions:  Completely oxidizes Acetyl CoA to CO2.  Produces NADH and FADH2 that are oxidized by the mitochondrial ETC to generate energy to form ATP.  Anabolic function: CAC is a source of biosynthetic intermediates. They can be used in the synthesis of glucose, fatty acids and amino acids. THE CITRIC ACID CYCLE THE CITRIC ACID CYCLE Each round consists of a series of 8 reactions that oxidize the acetyl group of acetyl-CoA to 2 CO2, 3NADH, 1FADH2 and 1 ATP Regulation: Activators Inhibitors ADP Citrate NAD+ ATP, NADH THE CITRIC ACID CYCLE ENERGY BALANCE 4 protons are required to synthesize 1 ATP Each NADH generates 2.5 ATPs Each FADH2 generates 1.5 ATPs For each Acetyl CoA 3 NADH  7.5 ATPs 1 FADH2  1.5 ATPs 10 ATPs 1 ATP THE CITRIC ACID CYCLE The citric acid cycle is an amphibolic pathway Intermediates can be used in the following anabolic pathways: Glucose biosynthesis Fatty acids biosynthesis Amino acids biosynthesis Amphibolic pathway: A metabolic pathway used in both catabolism and anabolism.