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Unformatted text preview: Chapter 17 organisms show marked similarity in the major pathways of metabolism types of organisms o phototrophs use light as energy source o chemotrophs use chemical compounds as energy sources chemoorganotrophs use organic compounds chemolithotrophs use inorganic compounds (always autotrophs) o autotrophs use CO 2 as carbon source o heterotrophs use organic compounds as carbon source metabolism : sum of chemical changes that convert nutrients into energy and chemically complex finished cellular products catabolism: oxidative degradation of complex organic nutrients to simpler oxidized energy-poor products; exergonic o ATP used directly for energy requiring processes; can be synthesized by substrate-level or oxidative phosphorylation substrate-level phosphorylation ( Step 10 of glycolysis) o NADH used to drive further ATP synthesis in oxidative phosphorylation See pg 17-4/5/6 in notes o NADPH used as source of reducing power for biosynthetic rxns anabolism: reductive synthetic process in which complex biomolecules are synthesized from simple precursors; endergonic glycolysis and TCA cycle are compartmentalized enzyme organization (options) o enzymes of a pathway are collected to form a discrete multienzyme complex (called metabolons) thus, intermediates arent lost/diluted o enzymes may be physically separate, soluble entities w/ diffusing intermediates o membrane-bound system: enzyme participants must diffuse in just the 2 dimensions of the membrane to interact w/ their neighbors amphibolic intermediates can be in both catabolism and anabolism anabolic pathway may not always match the catabolic pathway for the product o ex: glycolytic pathway has 10 steps, but gluconeogenesis has 7 steps reversed from glycolysis + 4 enzymes o pathways must be different (either completely or in key locations) b/c of equilibration...
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This note was uploaded on 02/09/2010 for the course BIOL 3361 taught by Professor Zhang/spiro during the Fall '08 term at Dallas.
- Fall '08