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1.1 Cell structure

1.1 Cell structure

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Question 52

An environmental scientist measures the concentration of the unicellular green alga Chlorella in a liquid culture from a bioreactor.

Here is the method used:

  1. Dilute 1.5 cm3 of the culture with distilled water to a total volume of 12.0 cm3.
  2. Place a drop of this diluted culture on a specialized counting slide.
  3. Place a coverslip over the slide to set a liquid depth of 0.1 mm.
  4. Count the number of cells within a 0.25 mm×0.25 mm0.25\text{ mm} \times 0.25\text{ mm}0.25 mm×0.25 mm square grid.

The scientist counted 25 Chlorella cells within the square grid.

Calculate the number of Chlorella cells in 1.0 mm3 of the undiluted culture. Give your answer in standard form.

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Markscheme

1.1 Cell structure Questions

  1. GCSE
  2. /Biology
  3. /1.1 Cell structure

163 exam-style questions on AQA GCSE Biology 1.1 Cell structure, covering 1.1.1 Eukaryotes and prokaryotes, 1.1.2 Animal and plant cells, 1.1.3 Cell specialisation, 1.1.4 Cell differentiation, 1.1.5 Microscopy, and 1.1.6 Culturing microorganisms. Each one has a worked solution and a mark scheme showing where the marks go.

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