L8_chp5_notes

L8_chp5_notes - How Cells Work Chapter 5 5.1 Inputs and out...

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How Cells Work Chapter 5 5.1 Inputs and out puts of Energy What Is Energy? Energy is a capacity to do work Different Forms of energy-Potential energy, Kinetic energy, Chemical energy What Can Cells Do with Energy? Energy inputs become coupled to energy-requiring processes Cells use energy for: Chemical work, Mechanical work, and Electrochemical work First Law of Thermodynamics state that -- The total amount of energy in the universe remains constant Energy can undergo conversions from one form to another, but it cannot be created or destroyed Entropy is a Measure of degree of disorder in a system The world of life can resist the flow toward maximum entropy only because it is resupplied with energy from the sun Second Law of Thermodynamics that - No energy conversion is ever 100 percent efficient The total amount of energy is flowing from high-energy forms to forms lower in energy One-Way Flow of Energy The sun is life’s primary energy source Producers trap energy from the sun and convert it into chemical bond energy All organisms use the energy stored in the bonds of organic compounds to do work Endergonic Reactions: Energy input required; ie energy in; eg: photosynthetic reactions
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Exergonic Reactions : Energy is released; energy out Products have less energy than starting substance The Role of ATP Cells “earn” ATP in exergonic reactions Cells “spend” ATP in endergonic reactions ATP/ADP Cycle When adenosine triphosphate (ATP) gives up a phosphate group, adenosine diphosphate (ADP) forms ATP can re-form when ADP binds to inorganic phosphate or to a phosphate group that was
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L8_chp5_notes - How Cells Work Chapter 5 5.1 Inputs and out...

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