1. Bellringer
Please grab your lab manual from the front table.

2. Macromolecule Lab Black: Carbon White: Hydrogen Tan/Purple: Oxygen
Silver: Nitrogen

3. Chemical Reactions and Enzymes

4. Learning Target
Explain the basic structure of proteins and discuss the role of enzymes in chemical reactions.

5. Chemical Reactions   Reactant Product + Reactant + Reactant Product
An interaction between 2 chemicals – chemical bonds are either broken or formed.
The two parts of a chemical reaction are the REACTANTS and the PRODUCTS. 
Reactant
Product +
Reactant +
Reactant
Product

7. Chemical reactions & energy
Chemical reactions & energy
Some chemical reactions release energy (Exothermic)
digesting polymers
Some chemical reactions require (Endothermic) input of energy
building polymers

8. 
Chemical Reactions
Activation Energy - the energy needed for a chemical reaction to start
Most reactions in our bodies require high energy to occur quickly enough to keep a cell working properly.
energy
released
by the
reaction
products
reactants

10. ENZYMES  Enzymes are catalysts!
Enzymes are proteins that do the body’s work!
Enzymes speed up chemical reactions by interacting with substrates to lessen the energy needed …
Most enzymes have names that end in “-ase”

11. 

12. Enzymes Act On Specific Substrates
Enzymes Act On Specific Substrates
Enzymes have specific shapes!
A specific substrate (the reactants) will fit in the enzyme’s active site.
Enzyme + Substrate: fit like a lock-and-key (called “induced fit”). 

14. Enzymes Work By Lowering Activation Energy
Enzymes Work By Lowering Activation Energy
Activation Energy is the energy needed to start a chemical reaction (An energy bump you must jump over to get going).
Ex: pushing a rock downhill (The enzyme acts as a crowbar)

17. Look at the energy graph below:
activation energy
without enzyme
with enzyme
energy
released
by the
reaction
products
reactants 
Talk it over question: What affect does an enzyme have?

19. Factors That Influence Enzyme Activity
Factors That Influence Enzyme Activity
Temperature pH Salt Concentration

20. Effect of Temperature 
Small increase in temperature increases molecular collisions, reaction rates
High temperatures disrupt bonds and destroy the shape of active site

21. Effect of pH: Talk it over
Which curve likely represents an enzyme in the stomach? Why?
Which curve likely represents an enzyme in the blood? Why?