Lesson 3.2.1.3.1

3.2.1.3.1 Microscopy, magnification and cell fractionation Quiz: AQA Biology, Unit 2

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 3.2.1.3.1, Microscopy, magnification and cell fractionation: 20 multiple choice questions for the AQA Biology (7402), Unit 2: Cells, written with Revision Ninja.

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The 20 questions

  1. What is the correct mathematical formula used to calculate microscope magnification?

    • Real size - image size
    • Real size / image size
    • Image size / real size
    • Image size × real size

  2. What does the resolution of a microscope measure?

    • Focal lens length
    • Light intensity gathered
    • Maximum magnification power
    • Minimum distinct distance

  3. Which microscope type provides the highest resolution?

    • Scanning electron microscope
    • Transmission electron microscope
    • Light microscope
    • Laser scanning microscope

  4. What does a scanning electron microscope primarily image?

    • Specimen surface
    • Internal organelles
    • Cell cytoplasm
    • Living cells

  5. What is the approximate resolution limit of a light microscope?

    • About 20 mm
    • About 200 nm
    • About 0.02 nm
    • About 2 nm

  6. What is the purpose of homogenisation in cell fractionation?

    • Denature enzymes
    • Stain membranes
    • Release organelles
    • Dehydrate cells

  7. Why must the fractionation solution be kept cold and isotonic?

    • Speed up diffusion
    • Prevent osmotic damage
    • Stop transcription
    • Increase pH

  8. What is the unit conversion for 1 micrometre expressed in nanometres?

    • 100 nm
    • 1000 nm
    • 10000 nm
    • 1 nm

  9. A cell has an image length of 40 mm when viewed at a certain magnification. Its actual length is 0.02 mm. What is the magnification?

    • 4000
    • 200
    • 20
    • 2000

  10. An image of a cell is 16 mm wide at a magnification of x800. What is the actual width of the cell?

    • 0.2 mm
    • 0.002 mm
    • 12.8 mm
    • 0.02 mm

  11. A mitochondrion appears 60 mm long in a micrograph at a magnification of x30000. What is its actual length?

    • 20 micrometres
    • 0.2 micrometres
    • 200 micrometres
    • 2 micrometres

  12. Which component sediments first during low-speed centrifugation?

    • Ribosomes
    • Nuclei
    • Mitochondria
    • Endoplasmic reticulum

  13. Why do ribosomes require higher centrifugation speeds than mitochondria?

    • Smaller size
    • Higher lipid content
    • Greater density
    • Positive charge

  14. Why are ribosomes not clearly visible using a light microscope?

    • Too transparent
    • Below resolution limit
    • Absorb no light
    • Constant movement

  15. What happens when magnification increases without a rise in resolution?

    • Higher contrast
    • Clearer detail
    • Larger blurred image
    • Brighter field

  16. Does doubling light microscope magnification always double visible detail?

    • Only for nuclei
    • Yes
    • No
    • Only with stains

  17. How do scientists identify preparation artefacts in electron micrographs?

    • Use higher voltage
    • Compare preparation methods
    • Warm the sample
    • Stain with iodine

  18. Which microscope type reveals internal cell ultrastructure most clearly?

    • Fluorescence microscope
    • Light microscope
    • Scanning electron microscope
    • Transmission electron microscope

  19. What property allows differential centrifugation to separate cell organelles?

    • Size and density
    • Magnetic susceptibility
    • Electrical charge
    • Colour and shape

  20. Why cannot living cells be viewed using a transmission electron microscope?

    • Vacuum kills cells
    • Rapid diffusion
    • Lack of pigments
    • Too much water

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