As I know, chlorophyll is green as it absorbs all wavelengths but green. It absorbs red, yellow, blue, purple, etc. Thus, the plant does not utilize green light.

i] Why is chlorophyll green? Is there 'chlorophyll' of other colors?

ii] Is the green chlorophyll an 'evolutionary mistake'?

iii] If chlorophyll was black, what effects would there be?

iv] What is the effect on non-visible electromagnetic-radiation?


  • $\begingroup$ Welcome to Chemistry! This seems like a homework question. We ‎have a policy which states that you should show your thoughts and/or efforts into solving the ‎problem. It'll make us certain that we aren't doing your homework for you. Otherwise, this ‎question may get closed. $\endgroup$ – bon Feb 16 '16 at 13:19
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    $\begingroup$ Really, this is a homework question @bon ? How so? $\endgroup$ – N A Feb 16 '16 at 13:20
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    $\begingroup$ Any question which is presented in the manner of 'here is a list of questions, give me the answers' is a homework question. You need to show that you have though about the questions beforehand and explain why you have difficulty answering them. $\endgroup$ – bon Feb 16 '16 at 13:27
  • $\begingroup$ It's rather too broad IMO $\endgroup$ – Mithoron Feb 16 '16 at 17:57

i] There is chlorophyll-b (yellow-green) and carotenoids (yellowish).

ii] The green chlorophyll isn't an evolutionary mistake (unless, of course, you take the viewpoint that evolution IS just mistakes). Plant's get plenty of sunlight. The sun is way stronger than indoor lights used to grow plants. They don't really need more energy from the sun. Plants actually have some pigments to dissipate light because they would otherwise absorb too much.

iii] Plants might absorb too much energy. Think wearing all black on a hot summer day, and standing out in the sun ALL day.

iv] Plants don't really use ultraviolet light as far as I know. With the ozone layer blocking most of the ultraviolet rays coming at us, it would be very strange if they did evolve to absorb ultraviolet light. This might also harm the plant. Infrared rays do reach plants, but they don't really do much to help in photosynthesis. Anyways, light has to travel through the cytoplasm of plants which is full of water, and visible light is best at travelling through water.

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  • $\begingroup$ For homework questions we have a policy where you do not simply post the answer without explanation but rather that you give hints that lead the asker towards their own solution. We are not a homework completion service. $\endgroup$ – bon Feb 16 '16 at 13:19
  • $\begingroup$ This was a question I actually asked myself while I was studying biology, which is why I don't feel it is a homework question @bon $\endgroup$ – N A Feb 16 '16 at 13:21
  • $\begingroup$ red algae are tuned for utilization of bluer spectrum, as redder spectrum is completely adsorbed at moderate sea depth. Not sure if they are tuned for UV specifically, but wouldn't be surprized. $\endgroup$ – permeakra Feb 16 '16 at 15:56
  • $\begingroup$ @bon This isn't a homework question and is not even in my syllabus (9th grade)... My bio teacher can't give me an answer... Decided to ask here. $\endgroup$ – darkspine Feb 20 '16 at 5:32

To give you a quick start and hint to your questions,

(i) Chlorophyll is green, because it reflects off the green light. Yes, there are chlorophyll of other colours. If you look at the absorption and action spectra of photosynthesis, you can see that there are chlorophyll a, b, carotenoid that absorbs various wavelengths of light.

See if you can use this to deduce the next 3 questions.

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