25_LectureOutline

25_LectureOutline - Introduction to Metabolism Cells break...

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Introduction to Metabolism Cells break down organic molecules to obtain energy Used to generate ATP Most energy production takes place in mitochondria Metabolism Body chemicals Oxygen Water Nutrients Vitamins Mineral ions Organic substrates Cardiovascular system Carries materials through body Materials diffuse From bloodstream into cells Metabolism refers to all chemical reactions in an organism Cellular Metabolism Includes all chemical reactions within cells Provides energy to maintain homeostasis and perform essential functions Essential Functions Metabolic turnover Periodic replacement of cell’s organic components Growth and cell division Special processes, such as secretion, contraction, and the propagation of action potentials The Nutrient Pool Contains all organic building blocks cell needs To provide energy To create new cellular components Is source of substrates for catabolism and anabolism Catabolism Is the breakdown of organic substrates Releases energy used to synthesize high-energy compounds (e.g., ATP) Anabolism
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Is the synthesis of new organic molecules In energy terms Anabolism is an “uphill” process that forms new chemical bonds Functions of Organic Compounds Perform structural maintenance and repairs Support growth Produce secretions Store nutrient reserves Organic Compounds Glycogen Most abundant storage carbohydrate A branched chain of glucose molecules Triglycerides Most abundant storage lipids Primarily of fatty acids Proteins Most abundant organic components in body Perform many vital cellular functions Carbohydrate Metabolism Generates ATP and other high-energy compounds by breaking down carbohydrates: glucose + oxygen carbon dioxide + water Glucose Breakdown Occurs in small steps Which release energy to convert ADP to ATP One molecule of glucose nets 36 molecules of ATP Glycolysis Breaks down glucose in cytosol into smaller molecules used by mitochondria Does not require oxygen: anaerobic reaction Aerobic Reactions Also called aerobic metabolism or cellular respiration Occur in mitochondria, consume oxygen, and produce ATP Breaks 6-carbon glucose Into two 3-carbon pyruvic acid Pyruvate Ionized form of pyruvic acid Glycolysis Factors
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Glucose molecules Cytoplasmic enzymes ATP and ADP Inorganic phosphates NAD (coenzyme) Mitochondrial ATP Production If oxygen supplies are adequate, mitochondria absorb and break down pyruvic acid molecules: H atoms of pyruvic acid are removed by coenzymes and are primary source of energy gain C and O atoms are removed and released as CO 2 in the process of decarboxylation Mitochondrial Membranes Outer membrane Contains large-diameter pores Permeable to ions and small organic molecules (pyruvic acid)
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25_LectureOutline - Introduction to Metabolism Cells break...

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