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CAIE A-Level Biology AS 3.1.5 Colorimetry in Enzyme Reactions Questions

Use colorimetry to measure enzyme reaction rates and interpret absorbance data from controlled investigations.

Syllabus
2028–2030
Course
Biology 9700
Level
AS

Exam points

  • Use colorimetry to measure enzyme reaction rates and interpret absorbance data from a calibration or time-course investigation.

CAIE A-Level Biology AS 3.1.5 Colorimetry in Enzyme Reactions Questions question 1

[Maximum number: 1]

A scientist investigated the progress of two enzyme-catalysed reactions in separate test-tubes, X and Y . Both reactions result in colour changes that can be detected using colorimetry.
0.5 cm30.5 \mathrm{~cm}^{3} samples were taken from each test-tube at the start of the investigation and at regular intervals for the next 5 minutes. Copper ions were added to each sample as soon as the sample was collected to inactivate the enzymes and stop the reactions from progressing further.

The absorbance of each sample was measured using a colorimeter.
The graph shows the results of this investigation.

Figure for Question CAIE A-Level Biology AS 3.1.5 Colorimetry in Enzyme Reactions Questions question 1 — CAIE A-Level Biology AS

Which statement is consistent with the results shown in the graph?

A

The substrate in test-tube X has a higher absorbance than the product.

B

The product in test-tube Y has a lower absorbance than the substrate.

C

The rate of the reaction in test-tube X increased with time.

D

The rate of the reaction in test-tube Y increased with time.

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