CAIE A Level Biology 9700 · Cell structure
A student uses a light microscope with an eyepiece graticule and a stage micrometer to measure onion epidermal cells. The stage micrometer has 100 divisions per mm. The student calibrates the eyepiece graticule: 50 eyepiece divisions correspond to 0.5 mm.
Define resolution and magnification. Explain how they differ, referring to the limitations of a light microscope compared to an electron microscope.
4 marks, so the mark scheme is looking for about 4 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.
Written by Markquill to follow the Cambridge International syllabus. Markquill is independent and is not affiliated with or endorsed by Cambridge International.