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Investigating diversity

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Question 12

A marine biologist investigated the diversity of symbiotic zooxanthellae in different coral colonies by comparing their photosynthetic pigment profiles. They used thin-layer chromatography (TLC) to separate the pigments extracted from a zooxanthellae sample.

The biologist was provided with the following materials:

  • A silica gel TLC plate
  • A ruler and pencil
  • A micropipette
  • A developing chamber with a gas-tight lid
  • Mobile phase X
  • 0.5 cm3 of the zooxanthellae pigment extract
1.

Describe how the biologist could use these materials to separate the pigments in the extract.

[4]
2.

When using mobile phase X, the biologist resolved five distinct pigment spots. When they repeated the procedure under identical conditions but using a different mobile phase, Y, they resolved six distinct pigment spots. Explain the difference between these two chromatograms.

[2]

Investigating diversity Questions

  1. A Level
  2. /Biology
  3. /Investigating diversity