Unit 2 Notes

Unit 2 Notes - Biology 1001 Dr Steve T TH 9:10-10:30 Chapter 6 Energy Flow in Cells What is energy Energy is the capacity to do work o Kinetic

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Biology 1001 Dr. Steve T TH 9:10-10:30 Chapter 6: Energy Flow in Cells What is energy? Energy is the capacity to do work o Kinetic energy = energy of movement Light Heat Electric o Potential energy = stored energy Chemical energy Batteries Positional energy Laws of Thermodynamics: Explains how energy moves through transitions 1st law: Conservation of energy – the amount of energy in a system remains constant 2 nd law: When converted from one form to another, useful energy decreases o Entropy (a measure of disorder) increases o A car takes 100 units of chemical energy (concentrated with low entropy) runs it through the engine and produces 75 units of heat energy and 25 units of kinetic energy (motion) with high entropy Energy Flow on Earth Energy input from the Sun (over 90%) o Photoautotroph (plants, other binary producers) o Heterotroph (consumers, decomposers) o Which produce energy output (mainly heat) The earth is not a closed system Why is it possible for living organisms to comply with the 2 nd law of thermodynamics? A. Chemical reactions inside cells always cause an increase of high-level energy B. Living organism are isolated systems and are not subject to the laws of physics C. The sun is the ultimate source of energy for most forms of life on Earth D. Living organisms are unique because they do not require energy for survival How does energy flow in Chemical Reactions? Chemical reaction is the forming and breaking of chemical bonds among atoms Reactants are the starting materials Products are the result of the reaction Exergonic Reactions (Fig. 6-2a) Chemical reaction that gives off energy Respiration is an example – sugar and oxygen are taken in and water and carbon dioxide are produced Activation energy is the energy needed to start the reaction Endergonic Reaction (Fig 6-2b) Chemical reaction that consumes energy
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Biology 1001 Dr. Steve T TH 9:10-10:30 Photosynthesis is an example – Begin with Carbon dioxide and water then energy is supplied by the sun and forms a sugar and oxygen which is then consumed by humans in respiration Coupled reactions (Fig 6-3) Exergonic reaction ATP (broken down to get) 100 units of energy released +ADP+P Endergonic reaction relaxed muscle + 20 units of energy contracted muscle Coupled reaction relaxed muscle +ATP contracted muscle+80 units of energy released as heat + ADP + P Which reaction is NOT an Exergonic reaction? Protein Synthesis Digestion Fire Movement How is cellular energy carried between coupled reactions? (Fig 6-4) Synthesis of ATP: Readily Available energy o A—P~P (ADP) uncharged battery o Add energy o Adds a phosphate and creates o A—P~P~P (ATP) charged battery Breakdown of ATP: releasing energy for work o A—P~P~P (ATP) o Releases energy o Looses a phosphate and creates o A—P~P (ADP) Coupled reactions within a living cells (Fig 6-5) Electron Carriers (Fig 6-6)
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This note was uploaded on 11/29/2011 for the course BIOL 1001 taught by Professor Minor during the Fall '08 term at LSU.

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Unit 2 Notes - Biology 1001 Dr Steve T TH 9:10-10:30 Chapter 6 Energy Flow in Cells What is energy Energy is the capacity to do work o Kinetic

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