First 244 words of the document:
CORE PRACTICAL 3
Purpose: To investigate how enzyme concentration can affect the initial rate of reaction.
1. Using a size 10 borer, cut pieces of potato which are 0.5cm in width.
2. Pour 20ml of hydrogen peroxide into a test tube.
3. Half fill the trough with water and fill a burette with water. Invert it over the trough of
water, with the open end under the surface.
4. Put some rubber tubing under the water into the burette, with the other end going
into a test tube (connected to a bung.)
5. Put the potato pieces into the test tube and immediately start the stop clock.
6. After 2 minutes record the change in water in the burette.
7. Repeat these steps several times and then again for different amounts of potato.
SAFETY: Wear eye protection and protect clothing from hydrogen peroxide. Rinse splashes
of peroxide off the skin as quickly as possible as it is an oxidising agent.
Amount of Amount of
potato disks. oxygen
1 2 3 4 Average
As the number of potato disks increases the amount of oxygen also increases'
therefore suggesting that enzyme concentration is directly proportional to rate of
reaction. The more enzyme molecules there are in a solution, the more likely a
substrate molecule is to collide with one and form an enzyme-substrate complex.