Testing the Rate of Reaction for Catalysts

Testing the Rate of Reaction for Catalysts

Introduction

Enzymes are produced in cells. They are proteins that act as

catalysts. Catalysts are chemical substances that speed up reactions

but do not get used up during the reaction. A single enzyme can be

used as many times over.

An example of how an enzyme molecule might join two other molecules

together and form a more complicated substance is shown below.

Reactions in which large molecules are created from small molecules

are called anabolic reactions.

When the new substance is formed the enzyme is released so it can

start another reaction. The two molecules might have combined without

the enzyme but if they did it would be very slowly. By bringing the

two substances closer together the enzyme speeds up the reaction. A

chemical reaction that would take hours or days to happen on its own

could take only a few seconds when the right enzyme is used.

Reactions in which large molecules are spilt into smaller ones are

called catabolic reactions.

Enzymes and biological catalysts are affected by the change in

temperature and pH. Acids and alkaline conditions alter the chemical

properties of proteins, including enzymes. Most enzymes work best at

particular level of acidity or alkalinity (pH). The protein -

digesting enzyme in your stomach for example works well at an acidity

of ph2. Most enzymes work best in neutral conditions (pH7).

I am going to find out how fast or slow the reaction according to the

concentration of hydrogen peroxide. I will make this experiment safe

by wearing safety goggles at all time through the experiment. I will

be using different concentrations of hydrogen peroxide and also

celery. It will be mashed up to speed up the reaction because it would

have a larger surface area. Enzymes are specific simply by an enzyme

acts on one substance will not act on a different substance. The

enzyme has a shape exactly fits the substance on which it acts, but

would not fit the other substance.