1. Proteins: Enzymes What is a chemical reaction? Do they happen on their own? If we stare at the piece of paper, are we going to be able to make the oxygen molecules in the air collide with the cellulose in the paper? What do we need to do? What are reactants? What are products?

3. Examples of exothermic reactions: Digestion of food releases energy All combustion reactions (fires) C + O2 CO2+ E Adding an alkali metal to water 2 Na + 2 H2O2 NaOH + H2+ E Condensation of water Explosion of bombs Examples of endothermic reactions: Melting of ice absorbs energy Dissolving ammonium nitrate in water( the essence of commercial cold packs)

4. Endothermic Reactions the reactants have less potential energy than do the products. Energy must be input in order to raise the particles up to the higher energy level. Energy + A + B --> AB

5. Exothermic Reactions the reactants have more potential energy than the products have. The extra energy is released to the surroundings. A + B --> AB + Energy

6. Enzymes Enzyme Catalyst Anything that speeds up the rate of a reaction by lowering the ACTIVATION ENERGY Activ. E: energy required for a chem. Rxn to start making products used to regulatethe rate (speed) of chemical reactions Protein that helps speed up a reaction that occurs in a biological system Name of enzymes end in –ASE all enzymes are proteins, but not all proteins are enzymes each chemical reaction in an organism requires its own specific enzyme enzymes are never changed by their reactions! Substrate Molecule/compound that attaches to enzyme Active Site Specific location on enzyme for substrate to attach Where the enzymatic reaction occurs Enzyme-substrate complex When substrate binds to active site of enzyme Products molecules produced at the end of an enzymatic reaction

7. Factors that Effect the Rate of Reactions Temperature Hot Breaks bonds that give proteins its tertiary structure DENATURES Cold Slow down chemical reaction (formation of enzyme substrate complex) pH Acids and bases produce OH- and H+ ions too many ions are present, the enzyme may be denatured (twisted and pulled so out of shape that it can no longer function) Inhibitors Non-competitive react with portions of the active site, changing of its shape Allosteric Inhibitors Change shape of the enzyme Attach to regulatory site (not active site) and change the shape of the entire enzyme (specifically the active site) Competitive look like substrate, bind to active site, but do not make the intended product

9. Acetylcholinesterase catalyzes the breakdown of the neurotransmitteracetylcholine at several types of synapses as well as at the neuromuscular junction — the specialized synapse that triggers the contraction of skeletal muscle. One molecule of acetylcholinesterase breaks down 25,000 molecules of acetylcholine each second makes possible the rapid "resetting" of the synapse for transmission of another nerve impulse.

11. Lock and Key Model

14. Class work! Label Each box! 2. 3. 4. 1. 5.

15. 1. Class Work!Label Boxes! 2. 3. 4. 5.