CP- Enzymes And pH

Question 1

What does the enzymes and pH experiment measure?

Answer 1

How the pH affects enzyme activity

Question 2

What is the method for the ‘Enzymes and pH’ core practical?

Answer 2

1) Put a drop of iodine in each well of a spotting tile
2) Place a Bunsen Burner on a heatproof mat and a tripod and gauze over it. Also, a beaker of water should be put and heated until its 35°C. Try to keep this temperature constant throughout the experiment
3) Use a syringe to add 3cm3 of amylase solution and 1cm3 of buffer solution (pH 5) to the boiling test tube .
4) Using test tube holders, put the boiling test tube in the water and wait 5 mins
5) Next, use a different syringe to add 3cm3 of starch solution to the boiling tube
6) Mix the contents of the Tube and start a stop-clock
7) Continuous sampling to test how long it asks fir the amylase to break down the starch
Take a Pipette and are afresh sample from the tube every 10 seconds and drop it into a spotting tile
8) When the iodine turns brown/orange starch isn’t present anymore
9) Repeat this experiment with different pH solutions of buffers to see how pH affects the time taken for starch to be broken down.

Question 3

What variables can you control in the ‘Enzymes and pH’ experiment to make it fair?

Answer 3

Concentration of amylase solution

Volume of amylase solution

Question 4

What is the formula for working out the rate of reaction?

Answer 4

Rate = 1000 / Time

OR

Rate = change / time