Markquill
Start free

CAIE A Level Biology 9700 · Cell structure

Cell structure: explain question

Explain5 marksChallenge

A student prepared a temporary mount of onion epidermal cells and viewed them using a light microscope. A photomicrograph was taken and printed with a scale bar of length 10 mm that represents an actual length of 25 µm. A cell in the photomicrograph measures 30 mm in length.

Explain how the student can use this information to determine the actual length of the cell. Then explain why, even with this method, the structure of ribosomes within the cell could not be resolved using the light microscope.

0 words · 5 marks

No account needed for your first marks. Your answer is used only to mark it.

How this question is marked

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.

More Cell structure questions

All Cell structure questions

Written by Markquill to follow the Cambridge International syllabus. Markquill is independent and is not affiliated with or endorsed by Cambridge International.