can any biology expert tell me the size of a chlorophyll molecule and the size of a photosystem ?
Can we refine your question a bit?
Since chlorophyll comes in different types - here is an article for non-scientists
I am guessing you want chlorophyll a.
Next: size is what? molar mass? nm in length(this changes under some circumstances)?
Phototosystem I or photosystem II or both?
If you actually read those links you will know what to ask AND get the answers, too. A win-win. Plus learning how to ask well-defined questions helps a lot in Science.
i read the 2 articles however none of them contained the answer i was looking for by SIZE what i meant was the (length) size of a chlorphyll a molecule in nanometres and the length of both photosystems taken individually in nanometres
You might be able to estimate the length of the complex based on the typical bond lengths involved. Alternatively, you could download the crystal structures of the photosystems, then measure the length of the chlorophyll molecules using a program like PyMol.
Size and Power of a Chlorophyll a molecule
Photosynthetica. October 2000 , Volume 38, Issue 1, pp 159- 160
As bound in the proteins of the thylakoid by the phytol "tail", chlorophyll a has an area of 1nm^2.
What I wanted you to see is that chlorophyll (anything) is really complicated and there are almost no simple answers. So, sometimes there are no simple answers for what seem to be simple questions.
The value above seems a little offbeat to me becuse I think the "area" is a function of the orientation of the molecule wrt the angle of the measurement. But I do not know for sure. Chlorophyll a is active when bound to specific proteins and when there are physically nearby pigments, all in a specific spatial orientations. Getting something like the paper had would be really diffcult in situ. My opinion only.
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