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Cellular Respiration Slide 2 Autotrophs and Heterotrophs Autotrophs producers Use simple inorganic compounds to produce complex organic compounds Use external source of NRG Types: Photoautotrophs Carry out photosynthesis Light as NRG source Chemoautotrophs Use oxidation of inorganic compounds (H 2 S, NH 4 + compounds and Fe 2+ compounds) as energy Heterotrophs - consumers Slide 3 Aerobes and Anaerobes Aerobes Organisms which utilize O 2 to oxidize substances in order to obtain energy Types: Obligate aerobes (must use O 2 at all times) most animals, fungi, some bacteria Facultative aerobes (use O 2, but also have anaerobic methods to produce NRG) yeast; even some human cells (use of lactic acid instead) Anaerobes Organisms that do not utilize O 2 for NRG Types: Obligate anaerobes (O 2 is poisonous) Facultative anaerobes (can be exposed to O 2 ) Slide 4 Digestion: Breaking Down Macromolecules into Monomers Slide 5 Glucose is converted to pyruvate in the cytosol. Pyruvate enters the mitochondria. Slide 6 Phosphorylation Types of Phosphorylation of ATP: Substrate-level: Transfer of phosphate group to ADP from a reactive intermediate Not coupled with oxidation Oxidative Production of ATP coupled with NADH or FADH 2 Requires chemiosmosis of H + ions across the matrix membrane (for the most part) Slide 7 Slide 8 Stage 1 of Cellular Respiration: Glycolysis (no O 2 needed!) In the cytosol First step: Glucose gets phosphorylated! This way it cant diffuse out of the cell Remember: Transport of glucose across the membraneTransport of glucose across the membrane PLUS: destabilization of the ether bond! End product: 2 molecules of pyruvate Net Reaction: Glucose + 2 ADP + 2 Pi + 2 NAD + - 2 pyruvate + 2 ATP + 2 NADH + 2 H + C 6 H 12 O 6 + 2 ADP + 2 Pi + 2 NAD + - 2 C 3 H 3 O 3 - + 2 ATP + 2 NADH + 2 H + Animation Slide 9 NRG yielding rxns Also this! NADH will be used to make later on more ATP Slide 10 In Summary: Energy Yielding Rxns 1. glyceralgehyde 3 phosphate + Pi + NAD+ 1,3 diphosphoglycerate + NADH NADH will be used to make more ATP in mitochondria 2. 1,3 diphosphoglycerate + ADP 3 phosphoglycerate + ATP 3. Phosphoenolpyruvate + ADP Pyruvate + ATP Slide 11 Net products from Glycolysis (per glucose) 2 pyruvate 2 NADH 2 ATP Total energy = -61.3 kJ Slide 12 If theres no O 2 Pyruvate Lactic Acid Slide 13 If there is O 2 Slide 14 Fates of Pyruvate Depend on organism and conditions Yeast Anaerobic (no oxygen) Pyruvate decarboxylase Makes alcohol Aerobic Makes acetyl CoA --- energy or fat Others Anaerobic Makes lactate Sore muscles Aerobic Oxidative decarboxylation of pyruvate into Acetyl Co A Acetyl Co A --- energy or fat Slide 15 The Krebs Cycle (aka TCA cycle) Pyruvate enters mitochondria and is converted to acetyl CoA (by acetyl coenzyme A) Note: Major amounts of acetyl CoA are also produced by the oxidation of fatty acids Acetyl CoA is completely degraded to CO 2 and H 2 O Metabolism is dominated by the Krebs cycle Slide 16 Krebs Cycle Per Glucose 2 full turns: 2ATP 8NADH 4FADH 2 Animation Slide 17