Warm-Up

1
Warm-Up

• Write down everything you know about enzymes
  (what are they made of, what do they do, what
  affects them, why are they important, etc.)

2
Objective

• You will be able to explain what an enzyme is and
  what factors effect it

3
Enzymes

• GT Biology

4
Enzymes are proteins that

• Increase the rate of reactions
• Reduce the amount of energy needed for a reaction
  to start (activation energy)
• This is called a CATALYST.

5
Enzymes

• Are only needed in small amounts and can be
  reused (they do not change)
• Can be denatured (broken down and permanently
  altered) if the conditions arent correct.
• Example
• -cooking an egg
• -high fevers cause brain damage
• -vinegar curdles milk

6
Naming Enzymes

• They end in ase (lipase, polymerase, catalase)
• They are named according to the substrate they
  react with.
• Example
• Lactase is the enzyme that breaks down lactose
  (milk sugar).

7
Enzyme Reactions

• An enzyme works with a substrate (another name
  for a reactant in a chemical reaction) to
  either
• a. Build molecules
• b. Break molecules apart

8
How Enzymes Work

• Active site part of the enzyme where the
  substrate fits.

Active Site
9
Enzyme-Substrate Complex

• This is what is formed when the enzyme and the
  substrate join together.

10
Enzyme-Substrate Complex Formation Models

• Lock and Key Model
• an enzyme will only work on one type of
  substrate.
• One enzyme? One substrate
• Example
• -Protease breaks down protein.

11
Enzyme-Substrate Complex Formation Models

• Induced-fit model
• The enzyme and substrate change shape slightly to
  fit tightly together and react.

12
http//www.stolaf.edu/people/giannini/flashanimat/
enzymes/enzyme.swf
13
Factors That Affect Enzyme Action

1. Amount of Substrate

Substrate runs out
The reaction steadily increases until the
substrate runs out
14
Factors That Affect Enzyme Action

• pH
• Different enzymes work better at different pHs.
• The wrong pH will cause denaturation

(Ex lemon juice in fruit salad)
15
Factors That Affect Enzyme Action

• Temperature
• Most enzymes work best at 37o C (body
  temperature)
• Too cool enzyme slows
• Too hot enzyme denature

(Ex a Fever or using a refrigerator)
16
Coenzymes

• organic substances (vitamins) needed by some
  enzymes in order to function.

17
Enzyme Animation

• http//www.kscience.co.uk/animations/model.swf

18
Enzyme Animation

• What do you predict will happen when each factor
  is changed?
• What did happen when each factor was changed?
• Why is it important that enzyme activity
  increases or decreases with a change in each
  factor?