photosynthesis

1.   Cornelius van Niel studied photosynthesis in purple sulfur bacteria.
a.   He found that CO2 and H2O do not combine directly during photosynthesis.
b.   He also found that oxygen and CO2 do not combine to release oxygen gas.
2.   Experiments using isolated chloroplasts and heavy isotopes of oxygen confirmed that the oxygen atoms released during photosynthesis come from water.
3.   Melvin Calvin found that radioactively labeled carbon dioxide is incorporated into plant carbohydrates, even in the dark.
4.   Therefore, photosynthesis consists of two independent reactions: the light-dependent reactions that generate oxygen from water and the Calvin cycle that generates sugar from carbon dioxide.
a.   The light-dependent reactions split water, make ATP, and reduce the electron carrier NADPH.
b.   The Calvin cycle (light-independent reactions) uses the energy in ATP and NADPH to reduce CO2 to carbohydrate.

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Thanks, just another quick question, are photosystem 1 and 2 by any chance part of the light dependant reactions or are they there own process.