energetics 1

energetics 1 - Animal physiology and the materials and...

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Unformatted text preview: Animal physiology and the materials and energy budget Organisms are enormously complex molecular assemblies that must exchange energy and materials with the environment: open systems: no exchange = no life Some exchanges are slow: atoms in the DNA of a brain cell Some are fast: half-life of water is days in a human, minutes in a small fish ALL must be carefully balanced! Energy and material exchange is a set of budgets : gains: heat, food, water, oxygen losses: heat, water, CO 2 , urine, feces Animal physiology is largely about how these exchanges are managed. IN: OUT: food oxygen water heat wastes CO 2 water heat Food eaten: 2-3 tons Oxygen used: 2 tons Water intake: 6-10 tons Heat produced: 7 million kilocalories (enough to heat 90 tons of water from room temperature to boiling) Clearly, a balanced budget is critical! bookkeeping for a adult woman (.05 tons) over 10 years: Animal physiology and the materials and energy budget Animal physiology and the materials and energy budget We focus on energy metabolism and the energy budget Measures both energy and materials: Food can be used to produce energy (by using chemical potential energy) or to build tissue Energy metabolism (metabolic rate) : the sum total of all biochemical energy transactions at a given time = rate of production and utilization of ATP Average human contains about 50 grams of ATP at a given time but makes and uses about 40 kilograms of ATP per day! About 5.5 X 10 20 ATP molecules -- 0.5 g -- per second. For most animals, budgets are not in balance only during: growth (change in body size or storage of fat) reproduction (production of offspring) Metabolism (metabolic rate) : the rate of production and utilization of ATP. Cellular respiration is the source of ATP for animals Glycolysis glucose Electron transport & Oxidative phosphorylation Krebs cycle no O 2 O 2 present ATP net 2 ATP ATP net 38 ATP 6 CO 2 6 H 2 0 HEAT 2 lactate HEAT Animal energy budgets Metabolism (metabolic rate) : the rate of production and utilization of ATP. Cellular respiration is the source of ATP for animals Glycolysis fats Electron transport & Oxidative phosphorylation Krebs cycle ATP CO 2 H 2 0 HEAT Animal energy budgets Metabolism (metabolic rate) : the rate of production and utilization of ATP....
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energetics 1 - Animal physiology and the materials and...

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