Outline Chapter 8

Outline Chapter 8 - Chapter 8 An Introduction to Metabolism...

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Chapter 8 An Introduction to Metabolism I. An Organism’s Metabolism transforms matter and energy, subject to the laws of thermodynamics a. Totality of an organism’s chemical reactions. b. Organization of the Chemistry of Life into Metabolic pathways i. Metabolic pathway – specific molecule, altered in series of defined steps, resulting in certain product. Catalyzed by specific enzyme. ii. Metabolism = material and energy resources of cell. Some metabolic pathways release energy by breaking down complex molecules. Catabolic pathways – breakdown pathways. Ex. Cellular respiration. iii. Anabolic pathways – consume energy to build complicated molecules from simpler ones – biosynthetic pathways. Example of anabolism is synthesis of a protein from amino acids. Catabolic and anabolic pathways are downhill and uphill avenues of metabolic map. Energy released from downhill reactions can be stored and then used for anabolic pathways. iv. Bioenergetics – study of how energy flows through living organisms. c. Forms of Energy i. Energy – capacity ot cause change. ii. Kinetic energy – energy associated with relative motion of objects iii. Heat/thermal energy – kinetic energy associated with random movement of atoms or molecules. iv. Potential energy – energy that matter possesses because of its location or structure. v. Chemical energy – potential energy available for release in a chemical reaction d. Laws of Energy Transformation i. Thermodynamics – study of energy transformations that occur in collection of matter ii. System – isolated system vs. open system. iii. The First Law of Thermodynamics 1. Energy can be transferred or transformed, but it cannot be created or destroyed 2. Principle of conservation of energy iv. The Second Law of Thermodynamics 1. Most energy is lost in heat for animals 2. Logical consequence of loss of usable energy during energy transfer or transformation is that each such event makes the universe more disordered 3. Second law of thermodynamics entropy – Every energy transfer for transformation increases the entropy of the universe
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4. Spontaneous – process that can occur without an input of energy – process cannot occur on its own is said to be nonspontaneous – happen only if energy is added to the system. For a process to occur spontaneously, it must increase the entropy of the universe. v. Biological Order and Disorder 1. Living systems increase entropy of surroundings 2. Organism takes organized forms of matter and energy from surroundings and replaces with less ordered forms 3. Ex. – animal obtains starch, proteins, and other complex molecules, breaks them down – CO2 and water released – small molecules with less chemical energy released. Heat generation = entropy. 4.
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This note was uploaded on 02/14/2011 for the course BISC 220L taught by Professor Herrera,mcclure during the Spring '07 term at USC.

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Outline Chapter 8 - Chapter 8 An Introduction to Metabolism...

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