Lec6notescomplete - Bio1A Dr McCray Chapter 8 An...

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Bio1A Dr. McCray Lec 6 complete notes 1 Chapter 8 An Introduction to Metabolism Energy of Life The living cell is a miniature chemical factory where thousands of reactions occur The cell extracts energy and applies energy to perform work Some organisms even convert energy to light, as in bioluminescence Metabolism transforms matter and energy Metabolism is an emergent property of life that arises from interactions between molecules within the cell Metabolism is the sum total of all an organism’s chemical reactions A metabolic pathway begins with a specific molecule and ends with a product Each step is catalyzed by a specific enzyme Catabolic and Anabolic Pathways Catabolic pathways release energy by breaking down complex molecules into simpler compounds Anabolic pathways consume energy to build complex molecules from simpler ones Bioenergetics is the study of how organisms manage their energy resources Forms of Energy Energy is the capacity to cause change Energy exists in various forms, some of which can perform work Kinetic energy is energy associated with motion Heat (thermal energy) is kinetic energy associated with random movement of atoms or molecules Potential energy is energy that matter possesses because of its location or structure Chemical energy is potential energy available for release in a chemical reaction Fig. 8-2 Thermodynamics Thermodynamics is the study of energy transformations A closed system, such as that approximated by liquid in a thermos, is isolated from its surroundings In an open system, energy and matter can be transferred between the system and its surroundings Organisms are open systems
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Bio1A Dr. McCray Lec 6 complete notes 2 Review of the Laws of Thermodynamics 1st Law : Principle of conservation of energy Energy can be transferred and transformed Energy cannot be created or destroyed 2nd Law : Every energy transfer or transformation increases the entropy (disorder) of the universe During every energy transfer or transformation, some energy is unusable, often lost as heat Fig. 8-3 Thermodynamics and living organisms Living cells unavoidably convert organized forms of energy to heat Spontaneous processes occur without energy input; they can happen quickly or slowly For a process to occur without energy input, it must
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This note was uploaded on 09/16/2010 for the course BIO 1A taught by Professor Mccray during the Fall '09 term at Merritt College.

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Lec6notescomplete - Bio1A Dr McCray Chapter 8 An...

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