CAIE A Level Biology 9700 · The mitotic cell cycle
A biologist is examining a chromosome from a root tip cell of an onion plant during the G2 phase of the cell cycle. Describe the structure of this chromosome, including the roles of DNA, histone proteins, sister chromatids, centromere, and telomeres.
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.
Describe means: Say what happens or what something is like, in order and with detail. You are not being asked why. If there is data, quote it: name the trend, then give figures with units at the points where it changes.
Written by Markquill to follow the Cambridge International syllabus. Markquill is independent and is not affiliated with or endorsed by Cambridge International.