Exam 3 Study Guide--Chapters 6-7

Exam 3 Study Guide--Chapters 6-7 - EXAM 3 MATERIAL Chapter...

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EXAM 3 MATERIAL Chapter 6—Matter and Energy Basics o Matter —anything that takes up space and has mass. The physical material of the universe. o Energy —the capacity to do work. o 2 major categories of energy: Potential energy —energy stored in matter because of its position or location. Can be stored in chemical bonds in biological systems. Kinetic energy —the energy of motion. Laws of Thermodynamics o The laws of thermodynamics describe the properties of energy. o Energy transfer by organisms is subject to two laws of thermodynamics: Fist Law of Thermodynamics —states that energy can be transferred and transformed, but it can’t be created or destroyed. The energy of the universe is constant. Second Law of Thermodynamics —states that every energy transfer or transformation makes the universe more disordered. Every process increases entropy at the cost of useful energy. o Entropy —the measure of disorder, randomness. o If every energy transfer loses usable energy, why doesn’t life on the planet simply run out of energy? The planet isn’t a closed system—energy is constantly flowing in from the sun. o Closed system —a system which is completely isolated from its surroundings. o Open system —a system that allows energy to be transferred between the system and the surroundings. Energy Flow in Chemical Reactions o In all chemical reactions you begin with one set of substances, reactants , and end with a different set of substances, products . A + B <--> C + D (Reactants) (Products) o Thermodynamics determines whether or not a chemical reaction will occur in the cell, and how much energy it will consume or release. o 2 types of chemical reactions: Exergonic —reactions that release energy. Reactants <--> Energy Released + Products o Releases energy. o Reaction is energetically downhill. o Spontaneous reaction. Ex: burning glucose. Endergonic —energy-requiring reactions. Reactants + Energy Used <--> Products o Requires energy. o Reaction is energetically uphill. o Non-spontaneous reaction (requires an energy source)
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Ex: photosynthesis. o Although exergonic reactions release energy overall, they may require some energy to get started. Activation energy —the amount of energy that reactant molecules must absorb to start a reaction. “Starter energy” in exergonic reactions. It takes less activation energy to burn glucose than it does for photosynthesis to occur. o Coupled reactions —chemical reactions which release energy can be coupled to chemical reactions which require energy. Glucose breakdown and protein synthesis. Controlling the Metabolism of Living Cells o Metabolism —the total of an organism’s chemical processes.
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Exam 3 Study Guide--Chapters 6-7 - EXAM 3 MATERIAL Chapter...

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