Flashcards · Biology · Cell Structure
Microscopy and Magnification
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Write the magnification formula.
Magnification = size of image ÷ size of real object.
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How do you find the real size from the image size and the magnification?
Real size = image size ÷ magnification.
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What is resolution?
How clearly two points that are close together can be told apart.
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Which has higher magnification and resolution: light or electron microscope?
The electron microscope.
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Name two disadvantages of an electron microscope.
It is large and expensive, and the specimen must be dead.
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Name an advantage of the light microscope.
It is cheap and easy to use, and living cells can be viewed.
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A ×10 eyepiece and a ×40 objective lens are used. What is the total magnification?
×400.
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How many micrometres are in 1 mm?
1000.
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How many nanometres are in 1 µm?
1000.
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Why is a stain used on a slide?
It makes the cell structures easier to see.
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Which objective lens should you start with?
The lowest power one, which gives the widest view.
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Which wheel do you use to find the image, and which to make it sharp?
The coarse focus wheel finds it, then the fine focus wheel sharpens it.
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Why is a coverslip lowered at an angle?
To avoid trapping air bubbles.
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How should a biological drawing be done?
Sharp pencil, clear single lines, no shading, labelled, with the magnification written.
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Label every part of this light microscope. 
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Name part X of the microscope and say what it does. The stage. It is the platform that holds the slide, kept in place by the clips.
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Name part X of the microscope and say what it does. The fine focus wheel. It makes small adjustments to give a sharp, clear image, after the coarse wheel has found it.