1. Chemical Reactions & Enzymes
Chapter 2-4
Chemical Reactions
&
Enzymes

2. I. Chemical Reactions H+ + OH-H2O Na + Cl  NaCl
A. Chemical reactions are processes that REARRANGE the atoms in one set of chemicals into different chemicals.
REACTANTS PRODUCTS
H+ + OH-H2O
Na + Cl  NaCl

3. B. Activation Energy-
Energy needed to get a reaction started. This determines whether a reaction will release or absorb energy.
Activation Energy
Chemical
Reaction

4. III. Catalysts- substance that
A. Speed up the rate of a
chemical reaction.
B. Does this by lowering
the activation energy.

5. C. Enzymes are BIOLOGICAL catalysts.
1. They speed up chemical reactions in organisms.
a. Some reactions are sped up more than 10 million times than they would be without enzymes!
b. Without enzymes, organisms would not get rid of waste fast enough, or get necessary materials fast enough to survive.

6. IV. Enzymes A. Made of proteins
B. Very specific to ONE TYPE of reaction.
C. Enzyme names usually end in “-ase”
Ex_____________
(also named for reaction it works on)
D. Can be reused for same reaction over and over.
Salivary Amalyse

7. V. How Enzyme Activation Works
A. The substance(s) on
which an enzyme works is
the substrate.
B. Active Site- specific place
on the enzyme where the
substrate fits/attaches.
C. The fit is VERY precise.
D. Once substrate attaches
to enzyme, enzyme can
cause reaction to happen
FASTER!!
E. Often referred to as the
“lock and key” (enzyme
& substrate) complex.
Products
Substrate
Active site
ENZYME
LOCK
KEY
KEYHOLE
ENZYME
SUBSTRATE
ACTIVE SITE
??Why are the products a different color?

8. Enzyme reactions enzyme + substrate
enzyme-substrate complex
enzyme + substrate
Products + enzyme
Are the products of the enzyme-substrate complex the same as
Or different from the products after the ES complex?________
What does that tell you has occurred? __________________
What happens to the enzyme after the reaction? ___________
different
A chemical reaction
Reused

9. Enzymes: Amoeba Sisters

10. VI. Enzymes can be denatured (change in shape) by changes in :
Changes shape of an enzyme so substrate(s) does not fit into active site.
A. pH (acidic or basic)
B. Temperature

11. VII. Enzymes are used for:
Digesting food
Making materials in cell
Releasing Energy
Transferring information to/from cells
FACT: Sperm need an enzyme to enter egg cell

12. Enzymes- a fun introduction - YouTube