Enzymes and pH - Practical Skills Flashcards
How is pH controlled?
By adding buffer solutions with different pH values
How is the rate of enzyme activity measured?
By testing the enzyme-substrate solution for the presence of starch at fixed intervals, to find the time taken for all the starch to be digested
Rate = 1/time
How is the presence of starch tested?
- Using iodine solution
- If starch is present, the solution turns from brown to blue-black
How can the reliability of the results be improved?
By repeating the practical at each pH at least 3 times and take a mean of the time taken to find the rate
How can the accuracy of the estimate of the optimum pH be improved?
By repeating the practical at smaller pH intervals around the estimated optimum pH
State the source of error in this practical
The time intervals between testing may be too long to accurately find the time taken for all the starch to be broken down
State the hazard and safety precaution in this practical
Iodine solution is an irritant. Avoid contact with skin and eyes.
