3) Investigating Enzyme Reactions

1. How to Investigate Enzyme Activity
You can investigate how pH affects the enzyme amylase (which breaks down starch) using this method:

  • Add iodine solution into a spotting tile’s wells (to detect starch presence).

  • Heat water in a beaker to 35°C using a Bunsen burner or water bath.

  • Mix amylase, buffer solution (at a specific pH), and starch in a boiling tube.

  • Use a pipette to sample the mixture every 30 seconds and drop it into iodine solution.

  • Stop when the iodine stays orange-brown (indicating starch has been broken down).

  • Repeat with different pH buffer solutions to see how pH affects the reaction speed.

Variable Type

Description

Dependant:

The pH level of the buffer solution used

Independant:

Time taken for amylase to break down starch

Control:

Temperature, concentration of amylase, volume of starch solution, concentration of buffer solution

BAMP:

Beaker's warm (set water to 35°C)
Add amylase, buffer, and wait (1 cm³ of each, wait 5 mins)
Mix starch, start clock, quick drop (add starch and mix, start timing)
Pick samples, check iodine's stop (check every 30 secs, until no starch)

2. How to Calculate the Rate of Reaction

  • Formula: Rate of reaction = 1000 ÷ time taken (seconds).