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Genetic information, variation and relationships between organisms

Genetic information, variation and relationships between organisms

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Question 3

A student wanted to investigate taxonomic diversity in marine phytoplankton by analysing their photosynthetic pigments. They were provided with the following materials to perform paper chromatography on a phytoplankton extract:

  • A strip of chromatography paper
  • A ruler and pencil
  • A capillary tube
  • A glass boiling tube with a rubber bung and hook
  • Solvent system A
  • 0.5 cm3 of the concentrated phytoplankton pigment extract
1.

Describe how the student should use these materials to separate the pigments in the extract.

[4]
2.

In the first run using solvent system A, the student resolved three distinct pigment spots. However, when they repeated the separation under identical conditions using a different solvent system, B, they resolved five distinct pigment spots. Explain the differences in the number of spots resolved by the two solvent systems.

[2]
Markscheme

Genetic information, variation and relationships between organisms Questions

  1. A Level
  2. /Biology
  3. /Genetic information, variation and relationships between organisms

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