1. Energy
Required by all organisms
May be Kinetic or Potential energy

2. Two Types of Energy Reactions

3. Endergonic Reactions
Chemical reaction that requires a net input of energy.
Photosynthesis
6CO2 + 6H2O  C6H12O O2
SUN
photons
Light
Energy
(glucose)

4. Exergonic Reactions ATP Chemical reactions that releases energy
Cellular Respiration
C6H12O6 + 6O2  6CO2 + 6H2O+
ATP
(glucose)
Energy

5. Enzymes

6. What Are Enzymes?
Most enzymes are Proteins (tertiary and quaternary structures)
Act as Catalyst to accelerates a reaction
Not permanently changed in the process

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

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

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

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

12. Active Site
A restricted region of an enzyme molecule which binds to the substrate.
Active Site
Enzyme
Substrate

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

14. Factors Affecting Enzyme Activity
Temperature pH
Cofactors & Coenzymes
Inhibitors

15. Temperature & pH
High temperatures are the most dangerous reactions & denature enzymes (Most like normal Body temperatures)
Most enzymes like near neutral pH (6 to 8)
Denatured (unfolded) by ionic salts

16. 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 of hemoglobin in order for it to pick up oxygen.

17. 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

18. 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