1.)What do enzymes do to the rate of a reaction? Slow them down.
Speed them up.
They do not affect the rate of a reaction.
They sometimes speed up the reaction and sometimes slow it down.

2.)The activation energy is the amount of energy needed to start a reaction. What do enzymes do to the activation energy of a reaction?
Lower it
Raise it
Don't affect it at all
Sometimes lower and sometimes raise

3.)What is a substrate?

A small enzyme.
A large enzyme.
What an enzyme works on.
The products of a reaction.

4.)What is the active site of an enzyme?

Where all inhibitors (no matter the kind) bind.
Where the substrate binds to the enzyme.
Where an enzyme is turned off.
Where an enzyme actively slows down all reactions.