ENZYMES

VACHS BIOLOGY

DO NOW

1. What type of reactions involve the breaking of chemical bonds?

2. Which type of reactions involve the making of chemical bonds?

3. What is activation energy?4. What are the differences between physical

reactions and chemical reactions?5. What factors can change the activation energy

of a reaction?

1. What is HAPPENING HERE?

2. ENZYMES: NATURE’S CATALYSTS

What is a CATALYST?

3. Catalyst: a substance that speeds up the rate of a chemical reaction.

4. Catalysts lower a reaction’s activation energy.

ENZYMES

AN ENZYME IS CALLED “NATURE’S CATALYST.”

… SO WHAT DO WE THINK ENZYMES DO?

ENZYMES5. Enzyme: proteins that speed up chemical reactions that take place in cells.- THEY LOWER THE ACTIVATION ENERGY OF A REACTION!!!

6. ENZYME: LACTASE

FUNCTION: Speeds up the breakdown of milk.

Connections: What does it mean to be “lactose intolerant”?

ENZYME: LACTASE

Without lactase, you can’t digest milk! Without lactase, it would take 78 MILLION YEARS TO DIGEST MILK!!!!!!!!

7. ENZYME: ALCOHOL DEHYDROGENASE

Predictions: What do you think this enzyme might do?

ENZYME: ALCOHOL DEHYDROGENASEFUNCTION: Alcohol dehydrogenase helps break down alcohol.

People who do not produce alcohol dehydrogenase experience “Alcohol Flush,” also known as an “Asian Flush.”

8. ENZYMES …

Enzymes either help break things down FASTER

OR enzymes help put things together FASTER

ENZYMES9. ENZYMES DON’T GET USED UP IN CHEMICAL REACTIONS! THEY ARE NOT PRODUCTS OR REACTANTS!!!

LACTOSE -------> GLUCOSE + GALACTOSE LACTASE

COLD CALLS:

11. What is/are the reactant(s) in this reaction?12. What is/are the product(s) in this reaction?13. What enzyme is CATALYZING this reaction?

How do ENZYMES WORK?

14. Each enzyme only works for ONE specific reaction- This is often called the lock and key model (Why?)

How do ENZYMES WORK?

15. Enzymes work by lowering the activation energy (energy required for a chemical reaction to happen).

ENZYMES VIDEO

http://www.youtube.com/watch?v=MjdIqDoDIYA&feature=relmfu

What is a Substrate?

16. A substrate is the reactant (starting molecule) of an enzyme-catalyzed reaction. 17. It fits into the active site of an enzyme.

LOCK AND KEY?

Which one is the lock? Which one is the key?

ENZYMES ANIMATION

http://www.lpscience.fatcow.com/jwanamaker/animations/Enzyme%20activity.html

18. Summary

Movement/Voices: “Restaurant,” sitting still

Instructions: Write a summary of the enzyme process, including the following vocabulary: catalyst, enzyme, substrate, active site, “lock and key,” chemical reaction, reactants, and products.

Success: Write in complete sentences, use all the vocabulary, and finish in 5 minutes!

Temperature

Our bodies work best at a certain temperature…

How do you feel when you have a fever??

How do you feel when you’re really cold?

Enzymes

Our bodies (and the enzymes we need) work best at a certain temperature and pH!

19. Factors that affect enzymes:1. Temperature2. pH3. Substrate concentration (amount of available

substrate)

Denature

Looking at the prefix “de” and the word “nature,” what predictions do we have for what this word means?

Think of “de-humidifying….”

Denature

20. When an enzyme is placed in extreme pH or temperature, it “denatures,” meaning it changes to shape.21.- When it changes shape, what happens to the

lock and key fit?- Will the enzyme be able to function?

Toothpickase Activity

Voices/Movement: “Restaurant,” pick one partner to collect your materials!

Instructions: Watch and listen as I describe the instructions on the board. They are also written on your lab sheets!

Success: Listen and read so you understand the instructions! Then work with your partner to finish your lab activity and answer all your questions in the time allowed!