ExpertMedium1 markStructured
AQA GCSE · Question 06.8 · Bioenergetics
There are two types of chlorophyll in leaves. Figure 10 shows the percentage of different wavelengths of light that the two types of chlorophyll absorb. Table 6 shows the colour of different wavelengths of light. Suggest the advantage to a plant of having two types of chlorophyll.
There are two types of chlorophyll in leaves. Figure 10 shows the percentage of different wavelengths of light that the two types of chlorophyll absorb. Table 6 shows the colour of different wavelengths of light. Suggest the advantage to a plant of having two types of chlorophyll.
How to approach this question
Look at the graph (Figure 10). Notice that the peaks for chlorophyll a (dashed line) and chlorophyll b (solid line) are at different wavelengths. What does this mean for the total amount of light the plant can use?
Full Answer
Having two types of chlorophyll allows the plant to absorb a wider range of different wavelengths of light for photosynthesis.
The graph shows that chlorophyll a and chlorophyll b have different absorption spectra. Chlorophyll b (solid line) has strong absorption peaks at around 480 nm (blue light) and 650 nm (orange-red light). Chlorophyll a (dashed line) has strong peaks at around 430 nm (violet-blue light) and 670 nm (red light). By having both types of pigment, the plant can effectively absorb light across a broader range of the visible spectrum than it could with just one type. This maximises the amount of light energy it can capture for photosynthesis.
Common mistakes
✗ Just saying "it can absorb more light" without mentioning the key idea of a wider range of wavelengths/colours.
✗ Stating that it can absorb green light well (the graph shows both pigments absorb green light poorly, which is why leaves appear green).
Practice the full AQA GCSE Biology Higher Tier Paper 1
52 questions · hints · full answers · grading
More questions from this exam
Q01.1A root is a plant organ. Plant roots contain many different types of tissue. What is a tissue?EasyQ01.2Tissue in the tip of a plant root contains stem cells. Stem cells can differentiate into any type...EasyQ01.3In the past many drugs were extracted from plants. Aspirin is a painkiller. Which plant does aspi...EasyQ01.4Scientists have extracted chemical A from the deadly nightshade plant. Chemical A can be used as ...MediumQ01.5A deadly nightshade plant has chlorosis (yellow leaves). The mass of chemical A found in the leav...Medium