2Chemical ReactionsIn order for chemical reactions to take place, enzymes must be present to help speed up the reaction.Chemical bonds connect atomsto make molecules.Chemical reactions can do two things:They can join atoms to make molecules.They can break bonds in molecules.The sum of all the chemical reactions that take place within a cell is referred to as the cell’s metabolism.
3Chemical ReactionsThe molecules or atoms at the beginning of a chemical reaction are called the reactants.The materials produced by the chemical reaction are called products.2H O H2OReactants Product
4Law of Conservation of Matter/Energy Matter and Energy cannot be created or destroyed in chemical reactions
5Energy-Absorbing vs. Energy-Releasing Reactions Endothermic ReactionEnergy-Absorbing ReactionEnergy-Releasing Reaction
6Enzymes Reactants Products Active sites The molecules or atoms at the beginning of a chemical reactions are called ______.EnzymesReactantsProductsActive sites
7Energy-Releasing Energy-Absorbing Chemical reactions in which the products have more energy than the reactants are called _________ reactions.Energy-ReleasingEnergy-Absorbing
8Which graph illustrates an energy-releasing reaction? Graph AGraph B
9Introduction to Enzymes Enzymes are proteins that act as biological catalysts.Catalysts - speed up chemical reactions.Enzymes- speed up chemical reactions in living things.
10Structure and Function of Enzymes A substrate is the molecule that the enzyme changes.It is the reactant a chemical reaction controlled by an enzyme!Each enzyme has an active site which is the place where the enzyme and substrate attach.
11Structure and Function of Enzymes During a chemical reaction, the enzyme helps the reactant turn into product, however, the enzyme is not changed.Enzymes can be used over and over again.ProductReactant/SubstrateEnzymeNo change in the shape of enzyme/ready to catalyze next reaction.
12Enzymes are specific types of which biological macromolecule? CarbohydratesProteinsLipidsNucleic acids
13The molecule on which an enzyme acts: CatalystSubstrateMetabolismHomeostasis
15Which shape is the product of the chemical reaction shown below?
16Enzyme SpecificityEnzymes are very specific. This means that each enzyme can only work on one substrate.For example:1. Maltase only breaks down maltose (a carbohydrate).2. Lipase only works on certain lipids.3. Protease only works on certain proteins.Does a specific enzyme work on more than one substrate?NO!!!
17Enzyme SpecificityTherefore you need thousands of different enzymes for the thousands of different chemical reactions in your body.The names of many enzymes (Amylase, Lipase, Pepsin, Trypsin) usually end in ase or in.
18Enzyme SpecificityThe diagram below shows the lock and key model of how enzymes work on a specific substrate.Just like every lock has one type of key that opens it, every substrate has one type of enzyme that works on it.
19How Enzymes Work Lower activation energy Energy that is needed to start a chemical reactionPuts substrates in a good position to make/break bonds with each other
20Reaction with enzyme vs. Reaction without enzyme
21The energy that is required to start a chemical reaction is called Endothermic energyExothermic energyEnzyme energyActivation energy
22How do catalysts speed up or facilitate chemical reactions? Lower the activation energyAdd energy to the reactionBreak hydrogen bonds in the chemicalsDecrease the number of reactants
24Enzymes and Their Environment Most cells function best within a narrow range of temperature and pH.At very low temperatures, enzymes work too slow.
25Enzymes and Their Environment At high temperatures or extremes of pH the enzymes lose their shape.What would happen if a key lost its shape?It wouldn’t turn or fit in the hole.What will happen if an enzyme lost its shape?It wouldn’t recognize or bind with it’s substrate.
26Enzymes and Their Environment When an enzyme loses its shape and can no longer work correctly, it has been denatured.
27Enzymes stop functioning if: They act on a substrateThey become denatured due to improper pH or temperatureThey catalyze too many reactionsThey bind with the wrong substrate
28Passive Endothermic Exothermic Denatured When proteins, such as enzymes, lose their specific shape they have become __________.PassiveEndothermicExothermicDenatured
29What is the optimum pH for the enzyme pepsin? 12.556.5trypsinpepsin
31Building Macromolecules Polymer – large biomolecules made by linking together a large number of the same type of subunitMonomer- small molecule that is a subunit of a polymer (building blocks)Chemical reactions link monomers together to build polymers or break down polymers into monomersEnzymes help speed up these reactions!!