CAIE A Level Biology 9700 · Cell structure
A particle isolated from a hot spring is found to be approximately 0.5 µm in diameter. Analysis reveals a cell wall composed of peptidoglycan, a region of circular DNA not enclosed within a membrane, and numerous ribosomes of the 70S type. No other membrane-bound structures are observed.
Explain why this particle is classified as a prokaryote, and not as a virus or a eukaryote.
6 marks, so the mark scheme is looking for about 6 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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