Syllabus Edition

First teaching 2023

First exams 2025

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The Microscope in Cell Studies (CIE AS Biology)

Exam Questions

3 hours44 questions
11 mark

Which of the statements about light microscopes are correct?

1

The magnification of a light microscope is limited by the wavelength of light

2

The resolution of a light microscope is limited by the wavelength of light

3

To calculate the magnification of a light microscope the eyepiece lens and objective lens magnifications are added together

  • 1 and 2

  • 1 and 3

  • 2 and 3

  • 1, 2 and 3

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21 mark

Which row correctly describes the magnification and resolution of an electron microscope in relation to a light microscope?

  magnification resolution
A lower higher
B higher lower
C higher higher
D lower lower

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    31 mark

    At approximately which magnification would the resolution of a light microscope become too low to produce a clear image?

    • cross times100

    • cross times200

    • x 400

    • cross times1500

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    41 mark

    Which of the following is not a step involved in the preparation of an onion cell specimen for viewing under a light microscope?

    • Place one edge of a coverslip on the slide and carefully lower the rest of the coverslip onto the specimen

    • Add a drop of iodine stain

    • Remove a layer of onion tissue that is one cell thick from a piece of onion

    • Add a drop of methylene blue stain

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    51 mark

    Specimens can be measured using eyepiece graticules and stage micrometers.

    Which of the following correctly describes the role of a stage micrometer?

    • Directly measuring the size of a specimen

    • Determining the size of the eyepiece graticule units

    • Determining the magnification at which at object is being viewed

    • A type of slide upon which a specimen can be prepared

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    61 mark

    A microscope has a resolution of 200 nm. 

    Which of the following organelles would not be resolved by this microscope?

    • Mitochondria

    • Lysosomes

    • Ribosomes

    • Chloroplasts

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    71 mark

    Which of the following is not a convention that should be used when producing biological drawings of cells?

    • Single, clear pencil lines should be used

    • Shading should be used to indicate light and dark regions of cells

    • Label lines should not have arrow heads

    • At least half of the available space on the page should be taken up by the drawing

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    81 mark

    Which of the options gives the resolution, in nanometres, of an electron microscope and a light microscope?

      electron microscope light microscope
    A 5.0 20
    B 5.0 200
    C 0.5 20
    D 0.5 200

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      91 mark

      A lysosome has a diameter of 0.4 µm.

      Which of the following gives the lysosome diameter in nm?

      • 4

      • 40

      • 400

      • 4000

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      101 mark

      Which of the following correctly defines the term resolution in light microscopy?

      • The size of the smallest object that can be seen

      • Twice the wavelength of the light used to illuminate the specimen

      • The shortest distance at which two objects can be seen as separate points

      • The product of the magnifications of the eyepiece and the objective lens

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      1
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      1 mark

      Which of the following descriptions of light and electron microscopes is not correct?

      • An electron microscope has a maximum magnification of x500 000

      • A light microscope has a maximum resolution of 0.2 µm

      • An electron microscope has a maximum resolution of 0.05 nm

      • A light microscope can resolve specimens that measure 200 nm in diameter

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      2
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      1 mark

      A prokaryotic cell with a diameter of 1 µm is magnified 50 000 times by an electron microscope.

      What is the diameter of the cell in the resulting electron micrograph?

      • 5 mm

      • 5 x 10-1 mm

      • 5 x 102 mm

      • 5 x 101 mm

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      3
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      1 mark

      The electron micrograph below shows the organelles in a leaf cell, as well as a scale bar and on-screen ruler.

      em-with-ruler

      What is the magnification of the image?

      • x7000

      • ×3570

      • x2800

      • x280

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      4
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      1 mark

      The electron micrograph below shows a root vascular system.

      The magnification of the image is x200 and Y has a diameter of 1 cm when measured using a ruler.

      screenshot-2023-04-28-094858

      What is the diameter of the cell labelled Y?

      • 100 µm

      • 50 µm

      • 10 µm

      • 5 µm

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      5
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      1 mark

      To view the actual width of a transverse section of a xylem vessel with a x40 lens, which steps are needed?

      1

      measure the width of the xylem vessel using an eyepiece graticule

      2

      calibrate the eyepiece graticule using a stage micrometer on x10 objective lens

      3

      convert from mm to µm by multiplying by 10-3

      4

      multiply the number of eyepiece graticule units by the calibration of the eyepiece graticule.

      • 1 and 2

      • 2 and 3

      • 1 and 3

      • 1 and 4

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      6
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      1 mark

      The electron micrograph of a bacterial cell has a 2 cm scale bar.

      bacteria-micrograph-with-scale-bar

      What is the magnification of the image?

      • 2 x 103

      • 2 x 104

      • 2 x 101

      • 2 x 105

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      7
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      1 mark

      Erythrocytes (red blood cells) have a diameter of 7 000 nm. Pancreatic cells have a diameter of 35 µm.

      Which of these statements about the relative sizes of these cells is correct?

      • The erythrocytes are 5 times smaller than pancreatic cells

      • The erythrocytes are 50 times smaller than pancreatic cells

      • The erythrocytes are 5 times larger than pancreatic cells

      • The erythrocytes are 50 times larger than pancreatic cells

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      8
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      1 mark

      The table shows some approximate units for measuring the diameters of alveoli, white blood cells and the width of cell walls.

      Which of the rows show the correct units for these structures?

        Diameter of alveoli Diameter of white blood cells Width of cell walls
      A mm µm µm
      B mm µm nm
      C µm nm µm
      D µm µm nm

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        9
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        1 mark

        The following statements describe slide preparation. 

        Which statement would not be relevant in the preparation of a wet mount for observation with a light microscope? 

        • Methylene blue is added to the specimen

        • A coverslip is placed on the specimen

        • The low power lens is above the object on the stage

        • A drop of water is added to the specimen

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        101 mark

        The following statements describe producing a scientific drawing.

        Which is not a correct statement about drawing scientifically?

        • The magnification should be stated

        • Label lines should have arrowheads

        • White, unlined paper should be used

        • Lines should be drawn with a smooth continuous line

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        1
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        1 mark

        The actual length of a cellular structure is 6 µm.

        A student was asked to write an equation that could be used to calculate the magnification of an electron micrograph of this cell structure. The student used the letters q to u in their equation.

        q = the length of the cell structure in the image in cm

        r = the length of the cell structure in the image in mm

        s = 1000

        t = 1/6

        u = 6

        Which of the following would be the correct equation to calculate the magnification?

        • q over s cross times u

        • q cross times s cross times t

        • fraction numerator r cross times s over denominator u end fraction

        • r over s cross times u

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        2
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        1 mark

        The diagram shows a stage micrometer (top) being used to calibrate an eyepiece graticule (bottom). The divisions on this micrometer measure 0.1 mm.

        qn-22

        A slide of a plant cell was placed on the stage in place of the stage micrometer. 

         What is the width of a single chloroplast shown on the slide below?

        qn23

         

        • 100 µm

        • 50 µm

        • 10 µm

        • 0.5 mm

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        3
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        1 mark

        Cells can vary considerably in diameter, e.g.

        • Eukaryotic cells, such as a white blood cell          1.5 x 101 µm
        • Prokaryotic cells, such as Streptococcus              7.5 x 102 nm

        Use these measurements to find the maximum number of each cell that could be arranged, end-to-end, along a 1 cm line.

          Number of white blood cells Number of Streptococcus cells
        A 6.7 x 100 1.3  x 102
        B 6.7 x 101 1.3  x 103
        C 6.7 x 102 1.3  x 104
        D 6.7 x 103 1.3  x 105

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          4
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          1 mark

          The image below shows an electron micrograph of a bacterial cell. The scale bar measures 2 cm and represents a length of 500 nm.

          bacteria-micrograph-ruler-scale

          CC BY 2.5, via Wikimedia Commons

          What is the actual length of the bacterial cell?

          • 0.002 μm

          • 2.4 μm

          • 24 μm

          • 4 μm

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          5
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          1 mark

          The diagram below shows the view through an eyepiece when a stage micrometer is used. This stage micrometer (shown here at the top of the image) has divisions that are 0.1 mm apart.

          qn-7

          The same eyepiece is used to examine a blood smear.

          How many of the graticule divisions will cover the diameter of a white cell of 12.5 µm?

          • 1

          • 4

          • 5

          • 10

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          6
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          1 mark

          A light microscope is used at a magnification of x400 and with a green light source that has a wavelength of 510 nm.

          The same specimen is viewed again under the same conditions, but with the light source switched to red light with a wavelength of 650 nm.

          What effect would this have on the magnification and resolution of the microscope?

            magnification resolution
          A stays the same increased
          B stays the same decreased
          C increased decreased
          D decreased increased

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            71 mark

            The diagram below shows a view through a microscope eyepiece with a graticule scale and a stage micrometer, using a magnification of x400.

            qn28

            Using the magnification of x400, a chloroplast was measured to be 4 eyepiece graticule divisions in length.

            How long is the chloroplast?

            • 4.0 x 102 µm

            • 2.5 x 10-1 µm

            • 2.5 x 10-2 µm

            • 1.0 x 101 µm

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            81 mark

            The diagram below shows a view through a microscope eyepiece with a graticule scale (bottom) and a stage micrometer (top).

            qn29

            What is the area of the field of view at this magnification?

            Note that π = 3.14

            • 2.0 x 105 µm2

            • 7.9 x 103 µm2

            • 4.9 x 102 µm2

            • 4.9 x 104 µm2

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            91 mark

            A student was using an eyepiece graticule with 100 small divisions and a stage micrometer with 50 divisions, each 0.04 mm apart.

            Using a x40 objective lens, the whole length of the stage micrometer lined up with 15 divisions of the eyepiece graticule.

            What is the length of the 100 division scale of the eyepiece graticule at this magnification?

            • 750 µm

            • 75 µm

            • 13 mm

            • 1.3 mm

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