1. Enzymes!
Make life possible

2. Background Chemical reaction
Reactants  Products
Ingredients  Cake
Example: Photosynthesis
Sunlight + 6CO2 + 6H2O  6O2 + C6H12O6
Activation energy – energy needed to get reaction started

3. Enzymes All actions: eating, running, thinking… depend on enzymes
Control all biochemical reactions (chemical reactions of life)
Protein that changes the rate of a chemical reaction

4. Enzymes Often speed up (increase) rate of a reaction  Catalyst
Lower the activation energy required to start the reaction
Ex. Speed up rate of food digestion (metabolism)
Cause molecules (substrates) to undergo a chemical change  form new substances - products

5. How they work Each enzyme only works on a specific substrate
Substrate-specific
Ex. Sucrase (enzyme) only works on sucrose (substrate)
Enzymes are named for the substrates they work on

6. Substrate-specific Enzyme Substrate Sucrase Sucrose Lactase Lactose
Amylase
Starch
Pepsin
Proteins
DNA polymerase
Joins nucleotides
Lipase
Fats (lipids)
In your book, turn to p. 918

7. Active site
Active site – where substrate binds to enzyme

8. Enzyme Activity Depends on…
Temperature
Human enzymes work best at 37 degrees C pH
If temperature or pH are too high or too low, enzyme cannot work properly and may be permanently damaged (denatured)