How do chlroplasts use the sun's energy to split H2O into H and O?

Question

Also, what are reducing equivalents?

Answer 1

I see from your other question that you are just starting chemistry.

Photosynthesis is extremely complicated, and takes place through a large number of different steps. It produces oxygen, as you say. It does not produce hydrogen as such, but converts carbon dioxide to sugars.

A simple (!) equation to describe this is

6 CO2 + 6 H2O = C6H12O6 + 6 O2

This means that six molecules of carbon dioxide react with six molecules of water to give you one molecule of a sugar that contains six carbon atoms, 12 hydrogen atoms, and six oxygen atoms, and at the same time to give you six molecules of oxygen, each one of which contains two atoms.

Any equation that describes a real chemical process has to be balanced for all the atoms, since atoms are neither created nor destroyed in a chemical process. For example, in the equation above, a total of 18 oxygen atoms go in and 18 come out.

If you want to know more about how chloroplasts work, look in any book that describes photosynthesis, or look up photosynthesis in Wikipedia, which I use a lot. However, that may tell you more than you can handle at the beginning.

Hope this helps!

Answer 2

The H and O aren't directly from the H2O, Chloroplasts also use glucose (C6H12O6). Electrons from glucose in the membrane of the thylakoid (part of a Chloroplast) are heated up by the sun. The electrons then leave that part of the membrane being picked up by a series of acceptors in the membrane the last step is to release the electrons which creates energy for the cell.

The glucose and water are re-arranged so the H and O aren't both from the same molecule.