Enzymes

Unit 2

What is an enzyme?

• An enzyme is a special protein

+

What are they made of?

• Enzymes are made of amino acids (just like proteins!!!)

The lock and key model

What do they do?

• Enzymes start or speed up the rate of a chemical reaction.

How do they do that?

• Enzymes lower the activation energy– They make it easier for the reaction to start

like lowering a hurdle

reaction (time)

ener

gy

(kJ)

Ea with enzyme

Ea without enzyme

What is a chemical reaction?

• A chemical reaction is where atoms are rearranged into a different order

– Reactants go into the reaction (left)– Products come out of the reaction (right)

Reactant 1 + Reactant 2 Product

How do they help with a chemical reaction?

• Enzymes match up to a single partner like a lock and a key– We say they are specific

+ ↔ ↔ +

enzyme

reactant

+enzyme-reactant

complex↔products

enzyme

+↔

What happens when they are done helping with the reaction?

• After enzymes help start or speed up the chemical reaction they wait around to help with another reaction– We say they are reusable

What hurts enzymes?

• Enzymes do not like changes in temperature.

• Enzymes do not like changes in pH.

What hurts enzymes?

What happens to an enzyme when temperature or pH changes?

• Enzymes denature (lose their shape, die) in extreme temperatures or pH.

normal denatured

heat

pH