If I put a green filter over a plant why does the rate of photosynthesis decrease?

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CoronationStreet
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#1
Report Thread starter 6 years ago
#1
Hey
I was doing a few past paper questions on photosynthesis, and stumbled across a question which I dont quite understand:

The question is about how different wavelengths of light effect the rate of photosynthesis, and it asks why a putting green filter over a plant reduces the rate of photosynthesis compared to putting a red filter??

My answer would be:
The green filter would absorb the red light for itself which the chlorophyll of the plant would usually capture, as well as this it reflects the green light and thus green light is mostly available to the plant. This reduces the rate of photosynthesis because chlorophyll does not absorb green light but reflects it thus this cannot contribute to photosynthesis, it will not excite electrons thus ATP and NADP will not be generated and this will intern effect LIS. Chlorophyll absorbs red light but if green filter is absorbing it for itself theres a lack of light available thus slower photosynthesis rate.

What do you think/ any other ideas?
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Asklepios
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#2
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This is basically correct but I think you're a bit confused in places

A green will let green light go through and absorb red and blue light. Chlorophyll utilises red and blue light, so the filter would mean there is less usable light energy
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CoronationStreet
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#3
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(Original post by Asklepios)
This is basically correct but I think you're a bit confused in places

A green will let green light go through and absorb red and blue light. Chlorophyll utilises red and blue light, so the filter would mean there is less usable light energy
So what bit am I wrong with? Are you saying that because of the green light ONLY green light is available to the plant, but it can photosynthesise this but just not as much so the rate of photosynthesis is reduced rather than stopped?
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Asklepios
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#4
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(Original post by CoronationStreet)
So what bit am I wrong with? Are you saying that because of the green light ONLY green light is available to the plant, but it can photosynthesise this but just not as much so the rate of photosynthesis is reduced rather than stopped?
You said a green filter reflects green light (true) but we're interested in the fact it mainly transmits green light. Apart from that nothing is wrong but you can make your answer more concise.

And yes, it would be better to say reduced rate as some photosynthesis can occur.
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