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Enzymes. pp 35-37, 57. Reactions (rxn) Review. Energy: the ability to do work Requires energy to start the reaction (activation energy, E a ). Why do potatoes turn brown?. How Enzymes Work. E nd in – ase (i.e. synthase, polymerase, helicase) Reduces the activation energy ( E a )
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Enzymes pp 35-37, 57
Reactions (rxn) Review • Energy: the ability to do work • Requires energy to start the reaction (activation energy, Ea)
How Enzymes Work • End in –ase(i.e. synthase, polymerase, helicase) • Reduces the activation energy (Ea) • Protein catalyst
Helps assemble the product OR disassemble the reactants • Not used up in the reaction and can be used over and over Substrate = reactant
Lock and key model: each enzyme specific to a chemical reaction • Induced fit hypothesis: changes shape when attached to the substrate (reactants)
Every reaction has reactants that yield products Reactants Products • Potatoes contain an enzyme called catalase which can break down hydrogen peroxide 2H2O2 2H2O + O2 • How do you know it was working?
Factors Affecting Enzyme Activity • Temperature • pH • Concentration of substrate or enzymes
Temperature • Increases activity only to a certain point • Call this optimal temp • Temp changes the shape of the protein (enzyme)
Acids and Bases • H2O H+ + OH- • Acids: H+ > OH- EX. HCl, H2SO4 • Bases: H+ < OH- EX. NaOH, Mg(OH)2
pHpower of Hydronium • Measures acidity (from 0-14) and how much H3O+/H+ is present. The closer to 0, the more the H3O +/H+ 0 up to 7 = acid 7 = neutral over 7 = base/alkaline
pH • Enzymes have a specific pH they can work within • Too low or too high pH and activity can slow or even stop
Concentration • More enzyme more work and more product • Point of saturation: enzymes can only work so fast even if you add more substrate • Max out on activity