BIO 101 1st Edition Lecture 14 Outline of Last Lecture I Cellular Respiration II Redox Reactions a Oxidation b Reduction III Four Stages of Respiration a Glycolysis b Transition to Mitochondria c Krebs Cycle d Oxidative Phosphorylation Outline of Current Lecture I Fermentation a Products of glycolysis II Respiration III Photosynthesis a Calvin cycle b Light reactions Chapter 9 cont Fermentation anaerobic catabolism of organic nutrients Glycolysis plus one or 2 more chemical reactions to regenerate NAD oxidized form of coenzyme Products of glycolysis 2 ATPs 2 pyruvates 2 NADH If O2 was present NADH would cash in electrons at electron transport chain and generate more ATP also regenerate NAD In absence of O2 cant run the electron transport chain because you NEED O2 as the final electron acceptor So how can the cell regenerate NAD so that it can continue glycolysis Electrons from NADH are transferred back to make one of two unique products 1 Lactic acid 2 Ethanol No ATP is generated by transferring electrons to pyruvate but it regenerates NAD so that glycolysis can continue Energy yield from fermentation 2 ATP glucose 2 examples of fermentation o Ethanol fermentation is used by yeast to make beer o Muscle cells that don t get enough O2 do lactic acid fermentation sore muscles BIO 101 1st Edition Chapter 10 Photosynthesis We have been talking about respiration overall equation Photosynthesis is the opposite with regard to the overall equation and energy Major goal of respiration convert stable chemical energy food into readily useable form ATP Major goal of photosynthesis convert light energy into stable chemical energy make food Although the goals are opposite the two processes share many mechanisms in common Photosynthesis is an important process all living things depend on itphotosynthetic organisms are at the bottom of the food chain They make their own food all other things have to eat other living things to stay alive Autotrophs self feeders produce food PRODUCERS Heterotrophs cannot produce own food rely on food produced by other living things CONSUMERS Plants are photoautotrophs make their own food using photosynthesis Plants ALSO do respiration i e they make their own sugar and then use respiration to convert it to ATP Animals including humans cannot do photosynthesis They ONLY do respiration Photosynthesis occurs on organelle called the chloroplast it has 2 layers of membrane Photosynthesis occurs in TWO STAGES 1 Calvin cycle 2 Light reactions ATP energy NADPH source of electrons The two stages are interconnected Calvin cycle uses CO2 to make sugar i e takes a simple highly oxidized molecule and makes a complex highly reduced molecule CO2 sugar BIO 101 1st Edition Simple needs energy complex Oxidized needs energy reduced The ATP and electrons for the Calvin cycle are produced during the light reactions
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