Amylase is an enzyme that catalyses the breakdown of starch into maltose.
As part of an investigation, starch suspension was heated in test tubes to different temperatures using a water bath.
Two drops of amylase solution were added to each test tube, and the time taken for the starch to be completely broken down was recorded.
Table 1 shows the results of this investigation.
| Temperature of the starch suspension in °C | Time taken for starch to be broken down in seconds |
|---|---|
| 20 | 240 |
| 30 | 150 |
| 40 | 80 |
| 50 | 120 |
| 60 | 360 |
Which of the following variables need to be kept constant in this investigation?
the volume of starch suspension and the time taken for starch to be broken down
the temperature and the time taken for starch to be broken down
the volume of starch suspension and the concentration of amylase
the temperature and the concentration of amylase
