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1.3 Enzymes

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Question 3
F

A student investigated the effect of pH on the activity of amylase.

This is the method used.

  • Put a drop of iodine solution into each well of a spotting tile.
  • Place a test tube of starch solution and a test tube of amylase solution in a water bath at 35 ∘C35\ ^{\circ}\text{C}35 ∘C for five minutes.
  • Add 1 cm3 of a buffer solution at pH 5 to the starch solution.
  • Add the amylase solution to the starch solution and start a stop clock.
  • Every 10 s, use a pipette to put one drop of the mixture into a well of the spotting tile.
  • Repeat using buffer solutions at different pH values.
a.

Give the independent variable in this investigation.

[1]
b.

Give two variables that the student should control.

[2]
c.

Describe how the student would know that all the starch had been broken down.

[1]
d.

Explain why the starch solution and the amylase solution were placed in the water bath before they were mixed.

[2]
Markscheme

1.3 Enzymes Questions

  1. GCSE
  2. /Biology
  3. /1.3 Enzymes

44 exam-style questions on Edexcel GCSE Biology 1.3 Enzymes, covering 1.3.1 Mechanism of enzyme action, 1.3.2 Denaturation of enzymes, 1.3.3 Factors affecting enzyme activity, and 1.3.4 Measuring energy in food by calorimetry. Each one has a worked solution and a mark scheme showing where the marks go.

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