Biology 102A

1. Biology 102A Enzyme Notes

2. Journal 5 • You have a big race to run tomorrow morning. What should you eat for dinner tonight and tomorrow morning? • Explain why you made these food choices.

3. Chemical reactions and Enzymes • Chemical reactions: change from one set of chemicals to another set of chemicals • Involves the breaking of bonds & the formation of new bonds • Activation energy: energy needed to get a reaction started

4. What is an ENZYME? • An enzyme is a special type of protein called a catalyst • Catalyst: substance that speeds up a reaction because it lowers the activation energy • cells use enzymes to speed up reactions • Very specific: usually only catalyzes one item called the SUBSTRATE

5. HOW DOES AN ENZYME WORK? • Enzyme comes in contact with substrate at certain spot called ACTIVE SITE • Fits together like a “lock & key” • Bonding at active site weakens the bonds in the substrate • Makes it easier to change substrate

6. What are enzymes used for? What regulates them? • Used for digestion, photosynthesis, & DNA reproduction • Regulated by changes in pH, temperature, other proteins, and chemicals

7. Quiz 5 • Enzymes are a form of ___. a. carbohydrate b. lipid c. protein • Enzymes can speed up a reaction, so they are called ___. a. catalysts b. reactants c. inhibitors • The area where the enzyme attaches to the substrate is called the ___. a. active site b. cohesion area c. vectors 4. If the enzyme is heated, it will change shape. This ___ not affect the ability of the enzyme to work. a. will b. will not • Enzymes work because they lower the ___. a. chemical reactant rate b. active site location c. activation energy