Igcse Model Questions Vol1 2021 Biology Question 3

A student is investigating how temperature influences the activity of the enzyme amylase in breaking down starch. The procedure is as follows: 1. Prepare 50 mL of 1 % starch solution. 2. Add 5 mL of amylase solution to the starch and place the mixture in a water‑bath set at the required temperature. 3. Start a stop‑watch as soon as the enzyme is added and, at 10‑second intervals, add a few drops of iodine solution until the mixture no longer turns blue (indicating starch has been digested). 4. Record the total time taken for the colour to disappear. The experiment is repeated at the temperatures shown in the table below, and the time taken for the starch to be completely digested is recorded. | Temperature (°C) | Time for starch to disappear (s) | |------------------|----------------------------------| | 0 | 120 | | 20 | 80 | | 30 | 45 | | 40 | 30 | | 50 | 35 | | 60 | 55 | | 70 | 110 | Using this data, answer the questions that follow.