5.2 Energy and Metabolism - or destroyed but only converted from one form into another If an object or process gains an amount of energy it does so at

1 Energy and Metabolism Metabolism - the total of all chemical reactions that occur in a cell or organism - includes: 1. catabolism 2. anabolism 1. Catabolism - the metabolic reactions that result in the breakdown of complex molecules into simpler ones (digestion); a degradative processes - energy is released (exergonic reaction) - e.g.: cellular respiration 2. Anabolism - the metabolic reactions that result in biosynthesis - the synthesis of organic molecules - energy is needed (endergonic reaction) - e.g.: photosynthesis Energy - the ability to do work Thermodynamics - study of energy flow - describes all of the energy transformations which accompany all of the physical processes and chemical reactions in the universe - the study of thermodynamic principles as they apply to energy transformations in biology is given a special name – bioenergetics - two laws: 1. The First Law of Thermodynamics The total amount of energy in the universe is constant. Energy cannot be created

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Unformatted text preview: or destroyed but only converted from one form into another. If an object or process gains an amount of energy, it does so at the expense of a loss in energy somewhere else in the universe 2. The Second Law of Thermodynamics The entropy of the universe increases with any change that occurs. Living things preserve their internal order by taking from the surroundings free energy in the form of nutrients or sunlight, and returning to their surroundings an equal amount of energy as heat and entropy. 2 Exergonic and Endergonic Reactions Exergonic Reaction-spontaneous -energy releasing reaction; energy is released-energy is released as reactants form products; products have a lower amount of energy than the reactants Endergonic Reaction-not spontaneous-energy-requiring reaction; energy is added-reactants with low energy content are converted into products with a higher energy level...
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