Edexcel GCSE Biology

Microscopy & magnification

Edexcel GCSE Biology revision on Microscopy & magnification. Aligned to the Pearson Edexcel GCSE Biology 1BI0 specification. This bank has 25 practice questions on this topic.

Sample questions (3 of 25)

  1. Question 1

    Why is it necessary to use a very thin layer of onion epidermis when preparing a slide for light microscopy?

    • A) To allow light to pass through
    • B) To prevent tissue degradation
    • C) To improve the image contrast
    • D) To protect the glass slide
    Show answer

    Answer: To allow light to pass through

    Light microscopes rely on light passing through the specimen to reach the objective lens. If the specimen is too thick, light is blocked, resulting in a dark or obscured view rather than a clear image of cellular structures.

  2. Question 2

    Which component of a light microscope is adjusted to increase the clarity of a blurred image at high magnification?

    • A) The objective lens turret
    • B) The fine adjustment knob
    • C) The coarse focusing dial
    • D) The stage clips position
    Show answer

    Answer: The fine adjustment knob

    The coarse adjustment knob is used for initial focusing at low power, while the fine adjustment knob is essential for high-power objectives. Using the coarse knob at high magnification risks damaging the slide or lens due to the extremely short working distance.

  3. Question 3

    What is the primary advantage of using an electron microscope compared to a light microscope?

    • A) Higher resolving power
    • B) Lower equipment costs
    • C) Easier sample preparation
    • D) Viewing living specimens
    Show answer

    Answer: Higher resolving power

    Resolving power is the ability to distinguish between two close points. Because electron beams have a much shorter wavelength than visible light, electron microscopes reveal sub-cellular organelles that are invisible under a standard light microscope.

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