Me neither, but this morning I was. I came across this wonderful website from our own ASU, which happens to be one of the world's leading research institutions in the field of photosynthesis.

Photosynthesis, as you know, uses sunlight to split water into hydrogen and oxygen, so that the hydrogen may combine with carbon dioxide to make carbohydrate and other food chemicals. Plants, algae and some bacteria then exhale the oxygen and we get to breath it in. The image is a schematic the whole thing from Professor Wim Vermaas' Introduction to Photosynthesis.