Describe6 marksChallenge
An experiment was carried out to investigate the effect of pH on the rate of starch hydrolysis by amylase. Equal volumes of starch solution and amylase solution were mixed at pH 7 and pH 5. Samples were taken every 2 minutes and added to iodine solution. The absorbance of the iodine-starch complex was measured using a colorimeter set to 620 nm. The results are shown in the table.
| Time (min) | Absorbance at pH 7 | Absorbance at pH 5 |
|---|---|---|
| 0 | 0.80 | 0.80 |
| 2 | 0.55 | 0.70 |
| 4 | 0.35 | 0.62 |
| 6 | 0.20 | 0.55 |
Describe how the colorimeter was used in this investigation and explain the principles of enzyme action that are demonstrated by the results.