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Chapter 8 notes

Chapter 8 notes - Amber Owens Biology Chapter 8 Notes An...

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Amber Owens Biology Chapter 8 Notes 9/5/07 An Introduction to Metabolism 1. The Energy of Life 2. An organism’s metabolism transforms matter and energy, subject to the laws of thermodynamics. 1.1.Organization of the Chemistry of Life into Metabolic Pathways 1.1.1. Cellular respiration is a process that drives the cellular economy by extracting the energy stored in sugars and other fuels. 1.1.2. Cells can then use the energy to perform tasks such as transport solutes across the plasma membrane or convert energy stored in organic molecules to light (bioluminescence) 1.1.3. In its complexity, its efficiency, its integration, and its responsiveness to subtle changes, the cell is peerless as a chemical factory. 1.1.4. Metabolism is the totality of an organism’s chemical reactions. It is an emergent property that arises from interactions between molecules within the orderly environment of the cell. 1.1.5. A metabolic pathway begins with a specific molecule, which is then altered in a series of defined steps, resulting in a certain product. Each step of the pathway is catalyzed by a specific enzyme. 1.1.6. Mechanisms that regulate enzymes balance metabolic supply and demand, averting deficits or surpluses of important cellular molecules. 1.1.7. Metabolism as a whole manages the material and energy resources of the cell. 1.1.8. Some metabolic pathways release energy by breaking down complex molecules to simpler compounds. These are called catabolic pathways . A major pathway of catabolism is cellular respiration, in which the sugar glucose and other organic fuels are broken down in the presence of oxygen to carbon dioxide and water. 1.1.9. Anabolic pathways (biosynthetic pathways) consume energy to build complicated molecules from simpler ones. The synthesis of a protein from amino acids is an example of an anabolic pathway. 1.1.10. Energy released from catabolic reactions can be stored and then used to drive the reactions of the anabolic pathways.
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Amber Owens Biology Chapter 8 Notes 9/5/07 1.1.11. Bioenergetics : the study of how organisms manage their energy sources. 1.2.Forms of energy 1.2.1. Energy is the capacity to cause change; energy is the ability to rearrange a collection of matter 1.2.2. Kinetic energy is energy that can be associated with the relative motion of objects. 1.2.3. Heat/Thermal energy is kinetic energy associated with the random movement of atoms or molecules. (light) 1.2.4. An object not presently moving may still possess energy. Energy that is not kinetic is called potential energy ; it is energy that matter possesses because of its location or structure. 1.2.5. Chemical energy is a term used by biologists to refer to the potential energy available for release in a chemical reaction. Complex molecules such as glucose are high in chemical energy.
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