1.10 Core practical: Effect of pH on enzyme activity Flashcards
What enzyme is used in the core practical: effect of pH on enzyme activity?
Amylase
Why is amylase used in the core practical: effect of pH on enzyme activity?
It breaks down carbohydrates such as starch into simple sugars (e.g. maltose)
What equipment is required in the core practical: effect of pH on enzyme activity?
- test tube
- bunsen burner
- stop watch
What material is required in the core practical: effect of pH on enzyme activity?
- 1% amylase solution
- 1% starch solution
- iodine solution
- labelled buffer solutions of different pHs
- 50ml of cold water
What is the method of the core practical: effect of pH on enzyme activity?
1- Place single drops of iodine solution on each well of a tray
2- Label a test tube with the pH to be tested. Place it in a water beaker with 50ml cold water and place this above a bunsen burner for 3 minutes
3- Place 2cm cubed of amylase solution, 2cm cubed of starch solution and 1cm cubed of the buffer pH solution in a test tube and start a stopwatch
4- After 10s, use a pipette to place a drop of the solution into one of the wells containing iodine solution. The mixture should turn blue/ black to indicate that starch is present and has not yet broken down
5- Repeat step 4 after another 10s. Continue repeating until the solution remains orange, and record time taken.
6- Repeat step 1-5 with a buffer solution of different pH
7- Record your results on a graph of pH (on the x-axis) and time taken to complete reaction (on the y axis)
Why do we use a bunsen burner and a water beaker in the core practical: effect of pH on enzyme activity?
To keep the solution at a relatively constant temperature throughout the reaction (as it is a control variable in this experiment)
What result do we expect to see in the core practical: effect of pH on enzyme activity?
The optimal pH of amylase will be at whichever pH the reaction completes in the shortest time (this should be somewhere around pH 7.0)
