Lecture 6 Notes

Lecture 6 Notes - BIO 202 Notes Lecture 6 Protein structure enzymes and catalysis Chapter 8 An Introduction to Metabolism 8.4 Enzymes speed up

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BIO 202 Notes Lecture 6: Protein structure, enzymes, and catalysis Chapter 8: An Introduction to Metabolism 1. 8.4 Enzymes speed up metabolic reactions by lowering energy barriers 1. Catalyst: chemical agent that speeds up a reaction without being consumed by the reaction 2. Enzyme: a catalytic protein 3. The Activation Energy Barrier 1. Chemical reactions involve breaking and forming bonds 1. Molecules must be changed into a highly unstable state before a reaction can continue 2. Free energy of activation, a.k.a. activation energy, E A 1. Initial energy required to start a reaction 2. Often supplied by heat absorbed from the surroundings 3. Transition state: reactants are activated 1. Unstable condition 2. Bonds broken 3. Peak energy 4. How Enzymes Lower the E A Barrier 1. Proteins, DNA, and other complex molecules… 1. Are rich in free energy 2. Have the potential to decompose spontaneously 3. Do not decompose because typical cell temperatures are too low to provide sufficient E A 2. Heat… 1. Speeds a reaction by allowing reactants to attain the transition state more often 1. Increases the speed of the reactant molecules so they collide more often and more forcefully 2. Thermal agitation of the atoms in the molecules makes the bonds more likely to break 2. Is not the solution for biological systems 1. High temperature denatures proteins and kills cells 2. All reactions would speed up, not only the necessary ones
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This note was uploaded on 10/13/2008 for the course BIO 202 taught by Professor Dean during the Fall '08 term at SUNY Stony Brook.

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Lecture 6 Notes - BIO 202 Notes Lecture 6 Protein structure enzymes and catalysis Chapter 8 An Introduction to Metabolism 8.4 Enzymes speed up

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