1. Chemical Reactions and Enzymes
Chapter 2

2. Chemical Reactions
Process that changes one set of chemicals into another set of chemicals
Reactants  Products
CO2 + H2O  H2CO3

3. Enzymes
Proteins that act as biological catalysts (speed up chemical reactions)

4. Enzymes
Cells use enzymes to
speed up chemical
reaction

5. Enzymes Enzymes are very specific (each enzyme has only one reaction
that it can help)

6. Enzymes Enzymes usually end in “ase” * Lipase (breaks lipids)
* Protease (breaks
proteins)
* Maltase (breaks
maltose into 2
glucose)

7. Enzymes Enzymes are not changed when they perform their function
(it can be reused!)

8. Enzymes
The shape of the
enzyme determines its
function

9. Enzymes Sometimes, high temperatures or
extreme pH values may affect the shape
of an enzyme molecule. This process,
called denaturing, will also make the
enzyme less effective, possibly even
useless.

10. Temperatures and pH Optimum temperature for most human enzymes is
37°C or 98.6°F
Optimum pH varies
based on location in
human body
Stomach protease = 2
Intestinal protease = 8

11. Substrate Enzyme Substrate Lipase Lipid Protease Protein Maltase
Maltose
Substance the enzyme
acts upon

12. How Enzymes Work:
Substrate molecules fit the exact shape of the enzyme active site (based on shape)
When this happens, an enzyme-substrate complex is formed
The substrate becomes separated into 2 or more separate molecules
The enzyme separates from the substrate and is ready for another use

13. How Enzymes Work

14. Lock and Key Model The active site on an enzyme and the
substrate must fit
perfect like a “lock and
key”