required practical 1 - rate of enzyme controlled reaction

Question 1

describe how pH can be controlled.

Answer 1

use a buffer solution and monitor using a pH meter at regular intervals.

Question 2

why were enzyme and substrate solutions left in water baths for 10 minutes before mixing?

Answer 2

so solutions equilibrate / reach the temperature of the water bath.

Question 3

describe a control experiment.

Answer 3

use denatured enzymes (e.g by boiling) and keep everything else the same.

Question 4

suggest a safety risk and explain how to reduce this risk.

Answer 4

handling enzymes may cause an allergic reaction - avoid contact with skin by wearing gloves.

Question 5

explain why using a colorimeter to measure colour change is better than comparison to colour standards.

Answer 5

its not subjective and its more accurate.

Question 6

explain a procedure that could be used to stop each reaction.

Answer 6

boil or add a strong acid to denature the enzymes.
put in ice to lower the activation energy so no enzyme substrate complexes form.
add a high concentration of inhibitors so no enzyme substrate complexes form.