1.1 Cell structure

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Question 21
Medium

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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1.1 Cell structure Questions

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