Calvin System (C3 Pathway) and C4 Pathway

[Sub-Zero120]

I recently received a small assignment in Biology. One of the many questions I need to answer is what does "C" stand for in the C3 and C4 Pathways involved in photosynthesis. I have come to two seperate ideas however I am not sure either of them are correct.

I believe that the "C" may stand for either Chlorophyll or Carbon. However, I cannot seem to find an article online which proves my thoughts. If you could please spare a minute if you know anything about the subject and leave me a comment or link.

Thanks

-Jonathan

[Tankfriend]

Well, as far as I remember from my own biology classes at school you should be looking for the Calvin Cycle and carbon fixation reactions.

http://en.wikipedia.org/wiki/Calvin_cycle
http://en.wikipedia.org/wiki/C3_carbon_fixation
http://en.wikipedia.org/wiki/C4_carbon_fixation

Concerning your theories about chlorophyll and carbon - both of them are partly right.
The Calvin Cycle is mainly working inside the chloroplasts (a close guess with chlorophyll ) of a plant but the actual substance that has an important part in this is carbon.

[Bernem]

The quick answer is that the "C" stands for Carbon the number stands for the number of carbons in the first product of the CO2 fixation:

3-phosphoglycerate in C3 plants (3 carbon-atoms)
and oxaloacetate in C4 plants (4 carbon-atoms)

Chlorophyll is not involved in CO2 fixation