They use visible light (400 – 700 nm). This is electromagnetic (EM) radiation.
The specific wavelengths depend on the pigments of an individual chlorophyll molecule. A pigment is any substance that absorbs light. The color of the pigment comes from the wavelengths of light reflected (so those not absorbed). Chlorophyll, the green pigment common to all photosynthetic cells, absorbs all wavelengths of visible light except green (510 nm), which it reflects, allowing our eyes to see it. All pigments have their own characteristic absorption spectra.
Chlorophyll is a complex molecule, and actually exists in a few different types and modifications. All photosynthetic organisms (so all plants, plust certain protistans, prochlorobacteria, and cyanobacteria) have chlorophyll "A," which does not absorb every wavelength.
This is where "accessory pigments" come into play. Chlorophyll "B" is an accessory pigment in all plants, as well as xanthophylls and carotenoids (the most well-known is beta-carotene). In other photosynthetic organisms, such as algae and certain protists, chlorophyll "C," "D," and "E" also exist.
The ubiquitous chlorophyll "A" absorbs everything from violet to blue (400 – 475 nm) on the high end, the reds on the low end (650 nm), and some out of the green through orange wavelengths (510 – 590 nm).
The carotenoids and chlorophyll "B" absorb some of the energy in the green wavelength (510 nm). So this leaves the question…. why not so much in the orange and yellow wavelengths? Both chlorophylls also absorb in the orange-red end of the spectrum (with longer wavelengths and lower energy).
The origins of photosynthetic organisms in the sea may account for this. Shorter wavelengths (with more energy) do not penetrate much below 5 meters deep in sea water. The ability to absorb some energy from the longer (so more penetrating) wavelengths might have been an advantage to early photosynthetic algae that were not able to be in the upper (photic) zone of the sea all the time. References : Geologist
March 6th, 2010 at 10:30 pm
Light (i.e. electro-magnetic radiation)
References :
March 6th, 2010 at 10:55 pm
They use visible light (400 – 700 nm). This is electromagnetic (EM) radiation.
The specific wavelengths depend on the pigments of an individual chlorophyll molecule. A pigment is any substance that absorbs light. The color of the pigment comes from the wavelengths of light reflected (so those not absorbed). Chlorophyll, the green pigment common to all photosynthetic cells, absorbs all wavelengths of visible light except green (510 nm), which it reflects, allowing our eyes to see it. All pigments have their own characteristic absorption spectra.
Chlorophyll is a complex molecule, and actually exists in a few different types and modifications. All photosynthetic organisms (so all plants, plust certain protistans, prochlorobacteria, and cyanobacteria) have chlorophyll "A," which does not absorb every wavelength.
This is where "accessory pigments" come into play. Chlorophyll "B" is an accessory pigment in all plants, as well as xanthophylls and carotenoids (the most well-known is beta-carotene). In other photosynthetic organisms, such as algae and certain protists, chlorophyll "C," "D," and "E" also exist.
The ubiquitous chlorophyll "A" absorbs everything from violet to blue (400 – 475 nm) on the high end, the reds on the low end (650 nm), and some out of the green through orange wavelengths (510 – 590 nm).
The carotenoids and chlorophyll "B" absorb some of the energy in the green wavelength (510 nm). So this leaves the question…. why not so much in the orange and yellow wavelengths? Both chlorophylls also absorb in the orange-red end of the spectrum (with longer wavelengths and lower energy).
The origins of photosynthetic organisms in the sea may account for this. Shorter wavelengths (with more energy) do not penetrate much below 5 meters deep in sea water. The ability to absorb some energy from the longer (so more penetrating) wavelengths might have been an advantage to early photosynthetic algae that were not able to be in the upper (photic) zone of the sea all the time.
References :
Geologist
http://biology.clc.uc.edu/Courses/Bio104/photosyn.htm
http://eosweb.larc.nasa.gov/EDDOCS/Wavelengths_for_Colors.html
http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookPS.html