1. Enzymes

2. Which property of water prevents living organisms from being frozen into a pond?
A High heat of vaporization
B High specific heat
C Cohesion of water molecules
D Ice is less dense than liquid water

3. What Are Enzymes? Most enzymes are Proteins
Act as Catalyst to accelerate a reaction
Not permanently changed in the process

4. Enzymes Are specific for what they will catalyze Are Reusable
End in –ase
-Sucrase
-Lactase
-Maltase

5. Enzyme-Substrate Complex
The substance (reactant) an enzyme acts on is the substrate
Enzyme
Joins
Substrate

6. Active Site
A active site of an enzyme molecule which binds to the substrate.
Active Site
Enzyme
Substrate

7. Induced Fit A change in the shape of an enzyme’s active site
Induced by the substrate

8. Induced Fit
A change in the configuration of an enzyme’s active site (H+ and ionic bonds are involved).
Induced by the substrate.
Enzyme
Active Site
substrate
induced fit

9. Checkpoint!
What is a catalyst?
What is the name for the substance in which the enzyme acts on?
Where does the substrate bind to the enzyme?

10. A water strider (insect) can skate along the top of a pond because:
A Hydrogen bonds result in cohesion
B Covalent bonds result in cohesion
C Water’s ability to maintain homeostasis
D Capillary action allows for adhesion

11. How do enzymes Work?
Enzymes work by weakening bonds which lowers activation energy

12. Enzymes Without Enzyme With Enzyme Free Energy
Progress of the reaction
Reactants
Products
Free energy of activation

13. How do enzymes work?
Enzymes can break down one reactant to form more than one product OR
Enzymes can bind more than one reactant to form one product

14. True or false: Checkpoint!
Enzymes speed up chemical reactions by increasing the activation energy of the reaction

15. Water has a high specific heat. What does this mean?
A It takes a lot of heat to form cohesion
B It takes a high temperature to cause evaporation
C Water’s temperature changes easily
D It takes a lot of energy to raise or lower the temperature of water

16. What Affects Enzyme Activity?
Three factors:
1. Environmental Conditions
2. Cofactors and Coenzymes
3. Enzyme Inhibitors

17. 1. Environmental Conditions
1. Extreme Temperatures are the most dangerous 2. pH (most like pH near neutral) 3. Ionic concentration (salt ions)

18. 2. Cofactors and Coenzymes
Inorganic substances (zinc, iron) and vitamins (respectively) are sometimes need for proper enzymatic activity.
Example:
Iron must be present in the quaternary structure - hemoglobin in order for it to pick up oxygen.

19. Two examples of Enzyme Inhibitors
a. Competitive inhibitors: are chemicals that resemble an enzyme’s normal substrate and compete with it for the active site.
Enzyme
Substrate
Competitive inhibitor

20. Inhibitors b. Noncompetitive inhibitors:
Inhibitors that do not enter the active site, but bind to another part of the enzyme causing the enzyme to change its shape, which in turn alters the active site.
Enzyme
Noncompetitive
Inhibitor
Substrate
active site
altered

21. Which of the following properties of water refers to two molecules of water stuck together by a hydrogen bond?
adhesion
cohesion
surface tension
capillary action