Lipase which converts fats into fatty acids and glycerol.
Amylase which converts starch/carbohydrates into glucose.
Protease which converts proteins into amino acids.
There are two tests which you can perform to test for enzymes. These are the Benedicts’ test which tests for sugars and the Iodine test which tests for starch.
Enzymes are biological catalysts which control chemical reactions. Enzymes are shaped like proteins. The shape is held together by weak hydrogen bonds which can be disrupted by heat and pH specifics (breakdowns in different pHs). They also have a specific ‘Active Site.’
Heat, the surface area and the concentration can affect the rate of the reaction. The reaction will increase if the temperature is increased because the heat energy gives the particles more energy, which means that there will be more movement in the particles.
Equipment
Bench mat Thermometer
Bunsen Burner Amylase & Starch Solution
Beaker with water 5 boiling tubes
Tripod Tongs
Gauze Boiling tube rack
Method
- Heat a boiling tube with 0.5 cm³ of amylase and a boiling tube of 4 cm³ of starch solution until it gets to 30°C. Incubate them and keep them at 30°C. After 2 minutes, mix the starch and amylase solution and take the mixed solution and drop 2 drops of it into a spotting tile with 2 drops of iodine (test for starch).
- Do the same as before but increase the temperature by 10°C (until it reaches 40°C).
- Repeat the experiment on the 3 other boiling tubes (increasing the temperature by 10°C).
- Record all of the results.
Variations
Keep the amount of solution and the number of drops of iodine the same but increase the temperature by 10°C each time.
Measure
The difference of the breakdown in the catalysis when they are heated at different temperatures.
Safety
Use rubber gloves when handling the solutions
Wear aprons
Wear goggles
Diagram of the apparatus
Results
Graph of results
Analysis of Graph
My graph shows that when the solution temperature was increased, the rate of reaction increased. This proves that my prediction was correct.
When the reaction rate reached it’s maximum, the reaction rate dropped quite quickly. In my results, the maximum reaction rate was 20°C, which occurred at 4 minutes 30 seconds.
Between 30°C and 60°C as the temperature increased. This was because the molecules in the solution were warmer and moved a lot more as they had more kinetic energy, which meant that there was going to be more collisions between the active site of both the amylase and the starch solution.
Above 60°C, the rate of reaction dropped quickly. This was because the higher the temperature, the amylase is destroyed more as it contains proteins and these proteins were almost all broken down.
Evaluation
My experiment, I thought went quite well except I had to add a few ice cubes when I over-heated the water bath.
If you increase the solution’s temperature, the reaction rate quickens. I learnt the smaller amount of solution you use, the reaction is much quicker and that the molecules in the solution were expected to collide with each other faster than if you heat up the same solution but with more concentration.
I have also learnt that the molecules are more likely to collide with each other if there is a smaller surface area or at a high temperature.
If I had a chance to improve my experiment, I would have increased the concentration level for both of the solutions or I could do an experiment to look for the presence of sugar.