Energy Enzymes Recall All living things need a

Recall… All living things need a source of, and use, energy Energy is used

Law of Conservation of Energy CANNOT be created or destroyed… …it can only CHANGE

Chemical Reactions A process that changes one set of chemicals into another set of

Chemical Reactions Reactants on the left Products on the right CO 2 + H

Chemical Reactions + Energy Every chemical reaction involves a transfer of energy Can be:

Endergonic Reaction Products have more energy than the reactants Energy is absorbed! Example: photosynthesis

Exergonic Reaction Products have less energy than the reactants Released as heat, light, or

Vocabulary Activation Energy: Amount of energy needed to start a reaction Catalyst: anything that

Enzymes PROTEIN catalyst found in living things (biological catalysts) HINT: Enzymes generally end in

Enzyme Specificity Lock and key: each enzyme is specific lock that only fits 1

Protein Denaturation Denature: To change a protein’s shape Example: scrambled eggs Recall that enzyme

What can denature a protein? Change in temperature (too hot, too cold) Change in

Enzyme inhibition Inhibitors: substance that prevents enzymes from working Competitive inhibition: Competes with substrate

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Energy & Enzymes

Recall… All living things need a source of, and use, energy Energy is used in series of reactions called metabolism

Law of Conservation of Energy CANNOT be created or destroyed… …it can only CHANGE form. The amount of energy in the universe remains the same over time.

Chemical Reactions A process that changes one set of chemicals into another set of chemicals. Can be Slow: ex: iron + oxygen rust Fast: ex: Hydrogen + Oxygen explosion

Chemical Reactions Reactants on the left Products on the right CO 2 + H 2 O H 2 CO 3

Chemical Reactions + Energy Every chemical reaction involves a transfer of energy Can be: Endergonic: absorption of energy Exergonic: release of energy

Endergonic Reaction Products have more energy than the reactants Energy is absorbed! Example: photosynthesis

Exergonic Reaction Products have less energy than the reactants Released as heat, light, or electricity Examples: Glow sticks, Hot hands (Exothermic)

Vocabulary Activation Energy: Amount of energy needed to start a reaction Catalyst: anything that lowers the amount of activation energy needed Unchanged or consumed during a reaction

Enzymes PROTEIN catalyst found in living things (biological catalysts) HINT: Enzymes generally end in -ase (Ligase, primase, lactase) Enzymes work as lock and key Image from: http: //www. cas. muohio. edu/~wilsonkg/old/gene 2005/syllabus_F 03_23. jpg

Enzyme Specificity Lock and key: each enzyme is specific lock that only fits 1 key (substrate) Substrate= reactant on which enzyme acts Area on the enzyme to which substrate “fits” is the active site

How enzymes work

Protein Denaturation Denature: To change a protein’s shape Example: scrambled eggs Recall that enzyme activity depends on shape… Shape changes, enzyme can no longer function

What can denature a protein? Change in temperature (too hot, too cold) Change in p. H

Enzyme inhibition Inhibitors: substance that prevents enzymes from working Competitive inhibition: Competes with substrate Noncompetitive inhibitors: Binding changes active site