A Level Biology Project
Aims
This is an experiment to examine how the concentration of the substrate hydrogen peroxide affects the rate of reaction of the enzyme catalase.
Background Information
Enzymes such as Catalase are protein molecules which are found in living cells. They are used to speed up specific reactions in the cells. They are all very specific as each enzyme just performs one particular reaction.
Catalase is an enzyme found in food such as potato and liver. It is used for removing Hydrogen Peroxide from the cells. Hydrogen Peroxide is the poisonous by-product of metabolism. Catalase speeds up the decomposition of Hydrogen Peroxide into water and oxygen as shown in the equations below.
Formula:
Catalase Hydrogen Peroxide---------------------->Water + Oxygen
Catalase 2H2O2------------------->2H2O+O2
It is able to speed up the decomposition of Hydrogen Peroxide because the shape of it's active site matches the shape of the Hydrogen Peroxide molecule. This type of reaction where a molecule is broken down into smaller pieces is called an anabolic reaction.
Apparatus Needed For The Experiments
1. Gas Syringe
2. Metal Stand
3. Yeast Catalase
4. Hydrogen Peroxide
5. Test Tubes
6. Beakers
7. Test Tube Rack
8. Stop Watch
9. Pipette
10. Pipette Filler
11. Tap Water
Method
To test out how the concentration of hydrogen peroxide affects the rate of reaction first set up the apparatus below.
1. Add 2cm3 of yeast to one test tube. Add 4cm3 of hydrogen peroxide solution at a concentration of 20% to the other test tube. Use a pipette to measure out the volumes. It is very important to accurately measure the amounts of Hydrogen Peroxide, Yeast and water to ensure a fair test.
2. Pour the hydrogen peroxide solution into the test tube containing the yeast and immediately put the gas syringe