A student investigated the effect of temperature on the activity of the enzyme amylase.She put 5 cm3 of starch solution, 1 cm3 of buffer solution and 1 cm3 of amylase solution in separate tubes in a water bath at the test temperature for 5 minutes. She then mixed them.Every 30 seconds she added one drop of the mixture to iodine solution on a spotting tile. She recorded the time taken until the iodine solution no longer turned blue-black.Her results are shown in the table.
(a) 1. More kinetic energy (of enzyme and substrate molecules).
2. More (successful) collisions between amylase and starch, so more enzyme-substrate complexes form per second.(b) 1. Hydrogen bonds (and ionic bonds) in the tertiary structure of amylase break, so the enzyme is denatured.
2. The shape of the active site changes.
3. Starch is no longer complementary to the active site, so no enzyme-substrate complexes form.
| Temperature / °C | 20 | 30 | 40 | 50 | 60 |
| Time taken for starch to be digested / s | 360 | 180 | 90 | 150 | not digested after 600 |
(a) 1. More kinetic energy (of enzyme and substrate molecules).
2. More (successful) collisions between amylase and starch, so more enzyme-substrate complexes form per second.(b) 1. Hydrogen bonds (and ionic bonds) in the tertiary structure of amylase break, so the enzyme is denatured.
2. The shape of the active site changes.
3. Starch is no longer complementary to the active site, so no enzyme-substrate complexes form.