CAIE A Level Biology 9700 · Photosynthesis
The table below shows the percentage absorption of light at different wavelengths for chlorophyll a and chlorophyll b extracted from a plant.
| Wavelength (nm) | Chlorophyll a absorption (%) | Chlorophyll b absorption (%) |
|---|---|---|
| 430 | 72 | 48 |
| 480 | 18 | 30 |
| 540 | 8 | 12 |
| 680 | 65 | 22 |
Outline how the absorption spectra of these pigments relate to the action spectrum of photosynthesis, and explain how the structure of the chloroplast is adapted to maximise the efficiency of the light-dependent stage.
7 marks, so the mark scheme is looking for about 7 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.