biol ch 6

biol ch 6 - Chapter 6 Energy Flow in Cells What is Energy?...

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Chapter 6 Energy Flow in Cells What is Energy? -Energy =the capacity to do work -Kinetic energy=energy of movement -Light (movement of photons) -Heat (movement of molecules; we see it as changes in temperature) -Electricity (movement of electrons through a conductor) -Potential energy=stored energy -Chemical energy (energy found in chemical bonds; when we break those bonds, energy is released. Ex. Gas in our car. We’re breaking bonds to move the car etc) -Positional energy- (ex. Standing on a diving board. We have positional energy when standing there, then some other sort of energy as we’re falling in the pool.) Laws of Thermodynamics 1. Conservation of energy -Amount of energy in a closed system remains constant. (aka, energy cannot be created or destroyed) 2. When concerted from one form to another, useful energy decreases -Enthropy increases (a measure of a order within a system. The order decreases) -Complex but organized. Taking in a lot of energy from the environment to keep things to organized. How efficient is your car (on average) at converting the energyin gas to kinetic energy? 1. 25% 2. 50% 3. 75% 4. 100% Why is it possible for living organisms to comply with the 2 nd law of thermodynamics? 1. Reactions inside cells always cause an increase of high-level energy. 2. Living organisms are isolated systems and aren’t subject to the laws of physics. 3. There is a constant input of energy from the sun 4. Living things are unique because they don’t require energy for survival. How does Energy Flow in Chemical Reactions? -Chemical reaction: forming and/or breaking chemical bonds among atoms -Reactions: starting materials -Products: result of the reactions Tuesday, September 26, 2006 Coupled Reactions -Exergonic reactions provide the energy needed for endergonic reactions. (figure 6-3) Which reactions is NOT an exergonic reaction? 1. Protein synthesis 2. Digestion 3. Burning log 4. ATP ADP+P (synthesis=building something up, which would make it an endergonic rxn)
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How is Cellular Energy Carried Between Coupled Reactions? Phosphorylation and ATP (figure 6-4) ATP Synthesis: Energy is Stored (figure 6-UN06) ATP Breakdown: Energy is released (figure 6-UN07) Electrons Carries- used to carry energy from one reactions to another -Takes in electrons from one reaction, and carries energy in the electrons to NAD+, it forms NADH, then transports electrons to a new reactions, where it deposits the electrons and can run an endergonic reaction. How Do Cells Control Their Metabolic Reactions?
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This note was uploaded on 04/28/2008 for the course BIOL 1001 taught by Professor Minor during the Fall '08 term at LSU.

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biol ch 6 - Chapter 6 Energy Flow in Cells What is Energy?...

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