mitochondria respiration chapter 3-4 shape highly variable can fuse or split structure outer membrane inner membrane cristae intermembrane space mitochondrial matrix free ribosomes respiratory enzymes mitochondria metabolic pathways reproduction can fuse or split DRP interacts with ER tubules oligomerizes at constriction point metabolism metabolic pathways usually in specific location convert substrates to end products via intermediates anabolic catabolic DRP ER tubule
Free energy, G Free energy, G redox reactions -reduction reactions reducing agent - electron donor oxidizing agent - electron acceptor cellular respiration combustion H + / O / O becomes oxidized (from food via ) + Controlled release of energy for synthesis of Explosive release of heat and light energy Electron transport chain becomes reduced / O (a) Uncontrolled reaction (b) Cellular respiration oxidizing agents NAD+ - (nicotinamide adenine dinucleotide) Nicotinamide (oxidized form) (from food) Dehydrogenase Reduction of Oxidation of Nicotinamide (reduced form) energy processing 3 stages to energy processing digestion of macromolecules breakdown of monomers or other precursor of CO and HO acetyl group pantothenic acid phosphorylated
glycolysis pyruvate - citric acid oxidative glycolysis - splitting of sugar energy investment energy payoff enzymes used kinase isomerase dehydrogenase mutase Electrons carried via and H Electrons Electrons carried carried via via Oxidative : and chemiosmosis Citric acid MTOCHONDRON MTOCHONDRON CYTOSOL Substrate-level Oxidative Substrate-level : Energy nvestment Phase 6phosphate Fructose 6phosphate of pyruvate Fructose,6bisphosphate Phosphoglucoisomerase Hexokinase PAYOFF glycolysis NVESTMENT cellular respiration Phosphofructokinase 4 3 preparation of pyruvate for citric acid pyruvate translocase pyruvate dehydrogenase complex 3 reactions MTOCHONDRON Aldolase CYTOSOL CO somerase to step 6 somerase 5 Dihydroxyacetone phosphate 3 + H+ x Pi x,3-bisphosphoglycerate 7 x Phosphoglyceromutase Phosphoglycerokinase Triose phosphate dehydrogenase 6 3-Phosphoglycerate 8 HO Enolase -Phosphoglycerate 9 Glyceraldehyde 3-phosphate : Energy Payoff Phase NAD+ Coenzyme A x x kinase Phosphoenolpyruvate (PEP) 0 Transport protein NAD+ + H+
sources of - used to fuel the citric acid catabolic sources pyruvate - from glucose glucose stored as glycogen fatty acid (spiral) digestion of amino acids NH 3 Proteins Amino acids Carbohydrates Sugars Glyceraldehyde 3- P Citric acid Glycerol Fats Fatty acids fatty acid spiral fatty acid activated Fatty acyl- synthetase carbons trimmed per turn steps activation hydration thiolysis activation thiolysis hydration Oxidative citric acid other names TCA, Krebs H + Citric acid CO + P i CO 3 3 + 3 citric acid stepwise oxaloacetate + acetyl --> (6 carbon) citrate decomposed back to oxaloacetate ketoglutarate dehydrogenase complex H + 7 Malate 6 Succinate 8 Oxaloacetate Fumarate Citric acid GTP 5 -SH GDP -SH P i Citrate -SH Succinyl 4 + socitrate 3 CO + α-ketoglutarate CO
Reduced coenzymes and H used to produce - account for most of the energy produced oxidative energy from redox reactions used to produce Protein complex of electron carriers H V + / O synth- ase electron tranport chain multiprotein complexes accept and donate electrons each time, electrons lose free energy pumped out chemiosmosis potential energy stored in gradient used to synthesize Free energy (G) relative to O (kcal/mol) 50 40 30 0 0 FMN H Cyt b Multiprotein complexes Cyt a V Cyt a 3 (originally from or H ) NAD+ (carrying electrons from food) + P i 0 + / O Electron transport chain Oxidative Chemiosmosis types of electron carriers flavoproteins cytochromes three copper atoms ubiquinone iron sulfur proteins Free energy (G) relative to O (kcal/mol) 50 40 30 0 0 0 FMN H Cyt b Multiprotein complexes Cyt a (originally from or H ) + / O V Cyt a 3 complex dehydrogenase flavin mononucleotide iron-sulfur protein complex succinate dehydrogenase H - lower energy complex cytochrome bc complex V cytocrome c oxidase 4 Protein complex of electron carriers (carrying electrons from food) H 4 H+ H+ V + / O - proton differential = ( per pair of e- ) H
proton motive force -synthase exergonic flow of H+ used to power production F0 0-4 subunits rotor turns F catalytic portion proton motive force NTERMEMBRANE SPACE H+ Stator Rotor F0 nternal rod F molecular mill F0 H+ flows into half channel binds with rotor subunits rotor turns F internal rod spins catalytic portion fixed F0 Catalytic knob F + Pi MTOCHONDRAL MATRX binding change mech. energy accounting catalysis of three binding sites three conformations (active about 3 molecules produced from glucose Electron shuttles span membrane site) loose MTOCHONDRON or H 6 binds with and P tight formed Citric acid H Oxidative : and chemiosmosis open released + + Maximum per glucose: CYTOSOL About 30 or 3 + about 6 or 8
anaerobic anaerobic what if there is no O? fermentation glycolysis -> pyruvate / pyruvate -> + P eukaryotes if O not available pyruvate undergoes fermentation reduced to lactate no release of CO OR i pyruvate -> reduced to EtOH release of CO NAD+ + H+ Lactate dehydrogenase Lactate related organelles related organelles peroxisomes similar to mitochondria in some ways form from pre-existing organelles import pre-formed proteins oxidative metabolism glyoxysomes specialized peroxisome in plants