CAIE A Level Biology 9700 · Cell membranes and transport
A signalling molecule (ligand) is released from a secretory cell and travels to a target cell, where it triggers a response. Describe the main stages of this cell signalling process, from the secretion of the ligand to the response in the target cell. In your answer, refer to the roles of any relevant components of the cell surface membrane.
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.
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.