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.)

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

Enzymes GT Biology

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.

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 aren’t correct. Example: -cooking an egg -high fevers cause brain damage -vinegar curdles milk

Naming Enzymes Example: 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).

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

How Enzymes Work Active Site Active site – part of the enzyme where the substrate “fits”. Substrate Enzyme Active Site

Enzyme-Substrate Complex This is what is formed when the enzyme and the substrate join together. Substrate Enzyme

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.

Enzyme-Substrate Complex Formation Models Induced-fit model The enzyme and substrate change shape slightly to fit tightly together and react.

http://www.stolaf.edu/people/giannini/flashanimat/enzymes/enzyme.swf

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

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)

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)

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

Enzyme Animation http://www.kscience.co.uk/animati ons/model.swf

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?