|Why no photosynthesis takes place in blue color
light, and why minimum photosynthesis takes place
in green color light, and Why the rate of
photosynthesis is maximum in red color light?
|Question Date: 2013-04-24|
That is a great question, light is a very
tricky thing as it comes in various forms of
energy levels. UV light (close to purple and blue)
is very high energy and that's why we get
sunburned. On the other side of the spectrum is
Infrared (close to red) which is seen in night
vision goggles and can be seen from heat emitting
from our bodies, a relatively low energy light.
Plants, just like us can only tolerate certain
wavelengths of light, especially for the chemical
reactions of photosynthesis. Photosynthesis occurs
when pigments, molecules in the plant cell, absorb
light photons and transfer them around to create
chemical energy. These pigments are picky in terms
of which light they can use. There are two types
of Chlorophyll pigments, A and B. Chlorophyll A
absorbs a lot of red and some blue while
Chlorophyll B absorbs a lot of blue and some red.
Neither absorb green much which is why plants
Chlorophyll absorbs red light. No light gets
absorbed by chlorophyll means the plant can't do
Trees and plants are green because of a green
pigment called chlorophyll. This pigment absorbs
red light the best, and converts the light into
energy that it uses for metabolism. As you likely
know, this pigment allows plants to use light as a
form of energy, as a part of a process called
photosynthesis. Instead of eating food to build
molecules, plants can take light from the sun and
use the energy to convert carbon dioxide from the
air into useful molecules! However, the pigment
doesn't strongly absorb blue or green light, so
plants can't use this energy for photosynthesis.
Interestingly, we know this even from the color of
plants! White light contains all the colors, and
plants appear green because they absorb the red
light, leaving what appears to us as green light,
to be seen by our eyes! If the light isn't being
absorbed by the plant, it can't be used for
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