Chapter 9 BIO notes

Chapter 9 BIO notes - Chapter 9 Cellular Respiration Harvesting Energy Life is work Living cells require transfusions of energy from outside

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Chapter 9: Cellular Respiration Harvesting Energy Life is work Living cells require transfusions of energy from outside sources to perform their many tasks (such as assembling polymers, pumping substances across membranes, moving and reproducing) -the energy stored in the organic molecules of food comes from sun, because energy flows into an ecosystem as sunlight and leaves as heat. -photosynthesis generates oxygen and organic molecule used by the mitochondria of eukaryotes (including plants and algae) as fuel for cellular respiration. Respiration breaks this fuel down, generating ATP. Waste products are carbon dioxide and water are the raw materials for photosynthesis. -3 key pathways for respiration: glycolysis, citric acid cycle, and oxidative phosphorylation 9.1 Catabolic Pathways yield energy by oxidizing organic Fuels Metabolic pathways that release stored energy by breaking down complex molecules are called catabolic Catabolic Pathways and Production of ATP Compounds that can participate in exergonic reaction can act as fuels o With the help of enzymes a cell can systematically degrade complex organic molecules that are rich in potential energy to simpler waste products that have less energy Fermentation: catabolic process; is a partial degradation of sugars that occurs without the use of oxygen. Aerobic respiration: most prevalent and efficient catabolic pathway: oxygen is consumed as a reactant along with the organic fuel. It is very similar to the combustion of gasoline after oxygen is mixed with the fuel. Cellular respiration includes both aerobic and anaerobic respiration Organic Compounds + oxygen carbon dioxide + water + energy Glucose is the fuel that cells most often use. The breakdown of glucose is exergonic, having a free energy change of -686 kcal per mole of glucose composed. (a negative ΔG indicates that the products of the chemical process store less energy than the reactants and the reaction can happen spontaneously. (without input of energy) Catabolic pathways do not directly move flagella, pump solutes across membranes, polymerize monomers, or perform other cellular work o To keep working, a cell must keep regenerate its supply of ATP from ADP Redox Reactions: Oxidation and Reduction -how do catabolic pathways that decompose glucose and other organic fuels yield energy? Based on its transfer of electrons during chemical reactions relocation of electrons release energy sotred in organic molecules, which is used to synthesize ATP The Principle of Redox: In a redox reaction, the loss of electrons from one substance is called oxidation and the addition of electron is called reduction. In the generalized reaction, substance Xe
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This note was uploaded on 07/10/2010 for the course BIO 204 taught by Professor O'neal during the Spring '07 term at SUNY Stony Brook.

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Chapter 9 BIO notes - Chapter 9 Cellular Respiration Harvesting Energy Life is work Living cells require transfusions of energy from outside

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