1. Ch. 6.3 Enzymes

2. Review Energy & Reactions ReactantProducts ReactantsProduct Exergonic reaction Endergonic reaction  Have less useable energy  Has more useable energy  Have less useable energy  Has more useable energy  This reaction releases energy  Energy absorbed Both reactions require energy to start = Activation Energy spontaneous  Can be  Cannot be

3. Graphs of Energy Change Activation energy Work is put in Fun is released More work than fun More fun than work Money is spent Money is received Spent more than received Received more than spent Initial Investment Good InvestmentBad Investment Time for reaction Energy

4. Catalysis The process of speeding up a reaction – how? Lowers the activation energy Works on both exergonic and endergonic “Catalyze” “Catalyst” Most important biological catalyst = By Enzymes

5. Enzymes (a type of protein) Quick Review Protein is a polypeptide chain of amino acids folded into a shape Shape provides function Enzymes subject to denaturation (unfolding) A.A.

6. If denatures (unfolds), then loses shape and loses function (loses site to bind) Polar A.A.NonPolar A.A.Polar A.A.

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8. How Enzymes Work Enzyme binds to substrate (“special” name for reactants that are catalyzed) Fit together like “lock and key” (shape determines…) May cause an “induced fit” – enzyme changes shape to better “hug” substrate Enzyme will push/pull on substrate(s) to weaken bond (more likely to break) or make bond more likely to form Lowers activation energy by making it more physically likely for reaction to occur… Active Site: area on enzyme (space or groove) where substrate binds to

9. The reactants an enzyme binds with are called A. proteins B. Substrates C. Active sites D. catalysts

10. The place where a substrate and an enzyme meet is called the A. Enzyme- substrate complex B. Catalyst site C. Active site D. P-site

11. When enzyme changes its shape to better fit its substrate this is called A. Active fit B. A catalyzed reaction C. Induced fit D. An allosteric reaction

12. The energy needed to start a chemical reaction is called A. Endothermic energy B. Exothermic energy C. Activation Energy D. Allosteric Energy

13. Which shape is the enzyme? 1. A 2. B 3. C 4. D AAA B C DD

14. Which shape is the active site? 1. A 2. B 3. C 4. D AAA B C DD

15. Which shape is the product? 1. A 2. B 3. C 4. D AAA B C DD