CAIE A Level Biology 9700 · Cell structure
A student observes onion epidermal cells using a light microscope. The table shows the typical resolution limits for a light microscope and a transmission electron microscope (TEM).
| Microscope | Resolution limit |
|---|---|
| Light microscope | 0.2 µm |
| TEM | 0.2 nm |
Explain the difference between magnification and resolution, and suggest why the electron microscope can resolve much smaller structures.
5 marks, so the mark scheme is looking for about 5 separate creditworthy points. Making the same point twice in different words earns it once.
Explain means: Give the reasons or the mechanism: why or how something happens. Link each point to the next with because, so or which means. A list of facts with no links usually loses the reasoning marks.
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