CAIE A Level Biology 9700 · Photosynthesis
The table below shows the percentage of incident light absorbed by chlorophyll a and chlorophyll b at different wavelengths of visible light.
| Wavelength (nm) | % Absorption by Chlorophyll a | % Absorption by Chlorophyll b |
|---|---|---|
| 400 | 70 | 60 |
| 450 | 25 | 80 |
| 500 | 10 | 20 |
| 550 | 5 | 10 |
| 600 | 15 | 25 |
| 650 | 80 | 30 |
| 700 | 35 | 10 |
Describe the absorption spectra of chlorophyll a and chlorophyll b as shown in the table, and describe how these relate to the action spectrum of photosynthesis.
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.
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