Bio1410 Ch6 Enzyme Outline PDF

Energy and Enzymes, Ch 6 (not on Exam 1) Energy (E) - Capacity to do work, can be converted from one form to another. In any energy conversion, some E is always lost Reactions: Endergonic: require an input of energy. (Products contain more E than reactants) Exergonic: relea...

Energy and Enzymes, Ch 6 (not on Exam 1) Energy (E) - Capacity to do work, can be converted from one form to another. In any energy conversion, some E is always lost Reactions: Endergonic: require an input of energy. (Products contain more E than reactants) Exergonic: release energy. ATP  Adenosine triphosphate = adenosine + 3 phosphate groups  Stores small amounts of E for short periods of time.  ATP is the unit of E used by the cell  Phosphate groups are held on with high energy bonds, which are broken via hydrolysis 1   When used for energy, a phosphate group is removed, leaving: Phosphate + ADP If Phosphate group is transferred to another molecule = Phosphorylation ATP is constantly regenerated. Enzymes  protein  catalysts  Speeds a reaction, but is not altered itself  Enzymes lower the amount of E required for reaction (activation energy)  Enzymes have specificity 2 Enzyme Action  Enzyme has active site – shape matches a specific substrate  Substrate - substance(s) on which the enzyme acts  Substrate binds at the active site Factors affecting enzyme function  Optimal Temperature  concentration of salt & other chemicals  Optimal pH  Cofactors & Coenzymes – help enzyme catalyze reaction Cofactors - often metal ions Co-enzymes – often vitamins 3 What regulates enzymes? 1. Amount of enzyme. More enzyme = greater rate of reaction. 2. Competitive inhibition - 2 substances compete to bind to the active site (substrate and inhibitor). When inhibitor is bound, the substrate can’t bind to active site. 3. Non-competitive inhibition - inhibitor binds to a site that is NOT the active site, changes shape of enzyme. 4. Feedback inhibition – (linked reactions) the final product inhibits an enzyme, and shuts down the series of reactions Oxidation & Reduction (Redox reactions) Oxidation – loss of electrons from a substance Reduction – addition (gain) of electrons to a substance Hydrogen atom = 1 electron and 1 proton 4 5