Anthony George
10TT
Biology Coursework
How does the amount of fat in milk affect the speed at which lipase works?
Lipase is an enzyme, which breaks down fat into fatty acids and glycerol. This diagram shows how you can use an indicator to show up the digestion of fats in milk.
Phenolphthalein is an indicator that turns pink in alkaline solutions of about pH 10. It will turn colourless in less alkaline solutions below pH 8.3. In this experiment the pink solution becomes colourless when digestion of fats produces enough acid to bring the pH below 8.3.
Plan
There are a few variables in this experiment; the enzyme works faster at body temperature, 37 Degrees Celsius, so if you changed the temperature of the experiment to body temperature, the whole experiment may work a lot faster. Another variation to this particular experiment would be to use different types of milk. Different milks have different fat contents so milk with a high fat content would take a long time to turn colourless whereas milk with a low fat content wouldn’t take that long to turn colourless because the lipase doesn’t have as much fat to break down.