CAIE A Level Biology 9700 · Photosynthesis
An electron micrograph of a chloroplast from a tomato leaf shows numerous flattened sacs (thylakoids) stacked into grana, surrounded by a semi-fluid stroma. Describe how the structural features of the grana and the stroma are adapted to their roles in the light-dependent and light-independent stages of photosynthesis respectively.
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.