1. enzymes

2. Enzymes are Proteins Many of our genes code directly for enzymes Estimated to be about 75,000 different types in the human body

3. Enzymes Do…. Do Not… Speed up chemical reactions Allow reactions to occur with less energy input Provide energy for the reaction End up altered or used up or in the product Change the net effect of the reaction (the products are the same with or without an enzyme)

4. So What Do Enzymes Do? They allow bonds to be broken at lower temperatures Thus they lower the activation energy So reactions can happen more easily with less input of energy (at lower temps) *this is why we are not on fire!

5. Enzyme Terminology Substrate = reactant Active site = place on enzyme where the substrate can bind

6. Enzymes are Specific! Only substrates that “match” the active site can be catalyzed Like a lock and key

7. How Do They Do it!?!?!? They may arrange the molecules to make it easier for bonds to break or collisions to happen They may change the environment (make it acidic etc.) May temporarily bond with substrate, stabilize the intermediates etc.

8. http://www.youtube.co m/watch?v=XTUm-75- PL4 http://www.youtube.co m/watch?v=XTUm-75- PL4

9. Fun with Enzymes: The Enzyme Catalysis Lab You will be testing how different factors affect the rate of an enzyme-catalyzed reaction http://www.youtube.com/watch?v=4FWa 6frjxl4 You will spend the rest of class today doing the pre-lab with your table. If you get to the procedure you will begin that alone and finish for HW http://www.youtube.com/watch?v=4FWa 6frjxl4

10. Your Experiment Should test how 1 factor affects the rate of hydrogen peroxide decomposition Should include 3 experimental trials and a control trial Should be conducted in a single block period (90 min) on A 10/31 or B 11/4 The standard reaction is about 1ml of peroxide with 1ml of catalase solution.

11. You Are Writing Your Own Procedure Needs to be thorough! Nothing is too small to put in procedures – i.e. put on glasses, rinse cups

12. Your Procedure Con. Set up your entire experiment at once – Make all of the catalase you need at once, put it into all the test tubes at once etc. Anything you will need to do should be in the procedure – I.e. rinsing cups, measuring amounts of water, how long you let the reaction run etc. Anything you will need to use should be in the procedure – i.e. graduated cylinder, scale etc.

13. Safety No open flames Goggles must be worn Immediately report any broken glassware!

14. Homework WP: 6.4- to review what I just presented Write a procedure for your lab