Chapter 5 Online lecture

Chapter 5 Online lecture - Ground Rules of Metabolism...

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Ground Rules of Metabolism Chapter 5
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Growing Old with Molecular Mayhem Free radical A molecule that has unpaired electrons Highly reactive, can disrupt structure of molecules
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Superoxide Dismutase Catalyzes the formation of hydrogen peroxide from oxygen free radicals and hydrogen ions Accumulation of hydrogen peroxide can be lethal to cells
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Catalase Catalyzes the formation of oxygen and water from hydrogen peroxide 2H 2 O 2 ----------> 2H 2 O + O 2
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Roundworm Experiments Diet supplemented with superoxide dismutase and catalase increased life span of normal worms Diet also allowed worms genetically-engineered for susceptibility to free radicals to live normal life span
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What is Energy? Capacity to do work Forms of energy Potential energy Kinetic energy Chemical energy
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What Can Cells Do with Energy? Energy inputs become coupled to energy-requiring processes Cells use energy for: Chemical work Mechanical work Electrochemical work
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First Law of Thermodynamics 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
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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
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Second Law of Thermodynamics No energy conversion is ever 100 percent efficient The total amount of energy is flowing from high-energy forms to forms lower in energy
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Entropy 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
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Energy Changes & Cellular Work Energy changes in cells tend to run spontaneously in the direction that results in a decrease in usable energy
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Endergonic Reactions Energy input required Product has more energy than starting substances product with more energy (plus by-products 60 2 and 6H 2 O) ENERGY IN 6 12
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Exergonic Reactions Energy is released Products have less energy than starting substance ENERGY OUT energy-rich starting substance + 60 2 products with less energy 6 6
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This note was uploaded on 04/28/2008 for the course BIOL 101 taught by Professor Hogan during the Spring '08 term at UNC.

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Chapter 5 Online lecture - Ground Rules of Metabolism...

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