BIOL 141 Chapter 6 Energy and Metabolism

BIOL 141 Chapter 6 Energy and Metabolism - Chapter 6 Energy...

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Chapter 6 Energy and Metabolism 1. Energy 2. Laws of thermodynamics 3. Free energy a. Endergonic reactions b. Exergonic reactions c. Activation energy 4. Enzymes a. Functions b. Enzyme activity i. Inhibitors/Activators ii. Competitive inhibition iii. Noncompetitive inhibition iv. Evolution of metabolism Energy : the capacity to do work Work : force times distance Two kinds of energy we will discuss Kinetic energy : the energy of motion, a boulder rolling down a cliff has lots of kinetic energy. Potential energy : stored energy, a boulder on the edge of a cliff has lots of potential energy. Energy can take several forms, mechanical, heat, sound, light, chemical, radioactivity. Heat is a good way to measure energy, because all form of energy can be converted to heat. Heat is the energy derived from the random motion of molecules Thermodynamics : The study of energy The unit of heat used in biology is the kilocalorie. One kilocalorie equals 1000 calories 1 calorie = the amount of heat required to raise one gram of water 1 degree Celsius The Calorie you see on food label is another term for kilocalorie, so if you look on a package of Mrs. Freshley’s powdered donuts (available in the vending machines at school) and you see it has 290 Calories, that means they have 290,000 calories Another unit of energy that is used in physics is the joule. Oxidation/Reduction Energy from the sun (sunlight) is converted into chemical energy via photosynthesis (glucose is the end product of photosynthesis). The chemical energy of the bonds is transfer during chemical reactions. When a molecule looses an electron it is oxidized. When a molecule gains an electron it is reduced. Oxidation/reduction reactions always occur together because the when an electron is transferred the one loosing it is oxidized and the one getting it is reduced. These kinds of reactions are called redox reactions. Redox reactions are very important; many key reactions in cells are redox reactions 1
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The Laws of Thermodynamics These are universal laws that describe how energy changes occur in the universe. These laws apply everywhere. You CANNOT violate these laws. Some people claim to build perpetual motion machines, or machines that put out more energy than they take it, this is BULLSHIT , because these machines violate to 1 st and 2 nd laws of thermodynamics. 1
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This note was uploaded on 10/20/2010 for the course PSYCH 101 taught by Professor Wyllie during the Fall '08 term at Delgado CC.

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BIOL 141 Chapter 6 Energy and Metabolism - Chapter 6 Energy...

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