CAIE A Level Biology 9700 · Classification, biodiversity and conservation
A biologist isolates two prokaryotic organisms: Organism X from a thermal spring and Organism Y from the human intestine. Preliminary tests show differences in their cell wall composition and membrane lipids. Outline the key differences between Archaea and Bacteria in terms of their membrane lipids, ribosomal RNA (rRNA) sequences, and cell wall composition.
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.
Outline means: Give the main points briefly. Less detail than describe, but every key step has to be there. One short line per step, in order. The marks are for coverage, not depth.
Written by Markquill to follow the Cambridge International syllabus. Markquill is independent and is not affiliated with or endorsed by Cambridge International.