Question

Chlorophyll a can absorb well in both the violet/blue end of the spectrum and the orange/red end of the spectrum. Why then is ultraviolet light considered a very good source of energy for photosynthesis?

- Chlorophyll b absorbs better in the violet/blue wavelengths.
- Ultraviolet light has more energy per photon.
- The sun produces more photons with a violet/blue wavelength than with a red wavelength.
- Chlorophyll b reflects orange/red light away from chlorophyll a.
- Carotenoids absorb better in the violet/blue wavelengths as well.

Answer 1

Ultraviolet light has more energy per photon than visible light, making it a potent source of energy, but it is not absorbed for photosynthesis due to its potential to damage pigments such as chlorophyll. Chlorophyll a and carotenoids mainly absorb light in the range of 700 nm to 400 nm, which is the photosynthetically active radiation range.

Step-by-step explanation:

Ultraviolet light is considered a very good source of energy for photosynthesis primarily because ultraviolet light has more energy per photon compared to light in the visible spectrum. The absorption of light by pigments like chlorophyll is essential for photosynthesis. However, the most effective wavelengths for photosynthesis are within the photosynthetically active radiation range, which is between 700 nm and 400 nm, corresponding to the visible light spectrum. Moreover, while chlorophyll a absorbs well at the violet/blue and orange/red ends of the visible spectrum, it does not absorb ultraviolet light for photosynthesis since UV light's energy is too high and can damage the pigments, a process known as bleaching. Additionally, carotenoids absorb well in the violet/blue wavelengths and play a complementary role in absorbing light energy.