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Magnification Questions

The document contains diagrams of an animal cell and a plant cell as seen under an electron microscope. It provides magnification factors to use in calculating real sizes of structures from their measured lengths on the diagrams. For the animal cell, calculations are shown determining the length of structure G to be 3 μm, the diameter of the nucleolus to be 2 μm, the diameter of the nucleus to be 9 μm, and the diameter of the cell to be 27-25 μm. For the plant cell, calculations of structure lengths and cell measurements are provided using a magnification factor of x625.

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2K views4 pages

Magnification Questions

The document contains diagrams of an animal cell and a plant cell as seen under an electron microscope. It provides magnification factors to use in calculating real sizes of structures from their measured lengths on the diagrams. For the animal cell, calculations are shown determining the length of structure G to be 3 μm, the diameter of the nucleolus to be 2 μm, the diameter of the nucleus to be 9 μm, and the diameter of the cell to be 27-25 μm. For the plant cell, calculations of structure lengths and cell measurements are provided using a magnification factor of x625.

Uploaded by

Omaima
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as DOC, PDF, TXT or read online on Scribd
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Cell Magnification

Fig. 1.2.1 below shows an animal cell

_________
5m

Fig. 1.2.1 Diagram showing the general structure of an animal cell as seen under the electron
microscope

1 Calculate the magnification factor

2 Calculate the length of structure G

3 Calculate the diameter of the nucleolus

4 Calculate the diameter of the nucleus

5 Calculate the diameter of the cell at its widest point

J. Groves 2010 – Adapted from Nelson AS Biology 1


The diagram below shows a plant cell

___________
40m

Fig. 1.2.2 Diagram showing the generalised structure of a plant cell as seen with an electron
microscope

1 Calculate the magnification factor.

2 Calculate the thickness of the cellulose cell wall.

3 Calculate the length of the cell.

4 Calculate the length of structure C.

5 Calculate the length of the vacuole.

2 Groves 2010 – Adapted from Nelson AS Biology


J.
Answers
1) Calculate the magnification factor
The line 5 m is 20 mm long. So 20 000 m = 5 m
Magnification is 20 000/5 = x 4 000.

2) Calculate the length of structure G


Length of G is 12 mm = 12 000 m
Magnification is x 4 000
Real size is 12 000/4000 = 3 m

3) Calculate the diameter of the nucleolus


Diameter is 8 mm = 8 000 m
Magnification is x 4 000
Real size is 8 000/ 4 000 = 2m

4) Calculate the diameter of the nucleus


Diameter is 36 mm = 36 000 m
Magnification is x 4 000
so real size is 36 000/4 000 = 9 m

5) Calculate the diameter of the cell at its widest point


109 mm = 109 000 m = 109 000/4 000 = 27–25 m
For all the answers above there is a tolerance limit of + or – 0.5mm, so + or – 0.1 – 0.2 m
There are other perfectly correct ways of doing the calculation, so if your method is
different, but arrives at the correct answer, then that is fine.

J. Groves 2010 – Adapted from Nelson AS Biology 3


Plant cell
1 Calculate the magnification factor.
The line representing 40 m is 25 mm or 25 000 m long
Therefore, magnification factor is 25 000/40 = x 625.

2 Calculate the thickness of the cellulose cell wall.


Wall is 3.0 mm = 3 000 m
Magnification is x 625
Actual thickness of wall is 3 000/625 = 4.8 m

3 Calculate the length of the cell.


120 mm = 120 000 m magnification factor is x 625
Actual length is 120 000/625 = 192 m

4 Calculate the length of structure C.


29 mm = 29 000 m magnification is x 625
Actual length is 29 000/625 = 46.4 m

5 Calculate the length of the vacuole.


80 mm = 80 000 m magnification is x 625
Actual length is 80 000/625 = 128 m.

4 Groves 2010 – Adapted from Nelson AS Biology


J.

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