CAIE A Level Biology 9700 · Cell structure
A student examines electron micrographs of a typical plant cell and identifies two types of ribosomes: 80S ribosomes in the cytoplasm and attached to the rough endoplasmic reticulum, and 70S ribosomes inside mitochondria and chloroplasts. Compare the 80S and 70S ribosomes in terms of their structure, location, and the origin and destination of the proteins they synthesise.
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.
Compare means: Give similarities or differences between two things, and say which side each point belongs to. Write each point as a pair, for example: A is X, whereas B is Y. Two separate descriptions rarely earn the marks.
Written by Markquill to follow the Cambridge International syllabus. Markquill is independent and is not affiliated with or endorsed by Cambridge International.