During Photosynthesis, Is Water Oxidized or Reduced?
Water goes through a very specific transformation during photosynthesis that you're going to want to pay attention to. Find out if water is oxidized or reduced during photosynthesis with help from an experienced biology professional in this free video clip.
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Hi, I'm Dan Weisenberger, and today I'd like to talk about during photosynthesis, is water oxidized or reduced. Now photosynthesis is a two step procedure by which light energy is converted into chemical energy in plants. As shown here in this schematic, if we zoom on a, this is supposed to be a leaf, if we zoom in on a cell within that leaf, we see that in the chloroplast, which is a specialized organelle of the cell, and specifically within the psycloid membrane, we see that there are pigments called chlorophyll which absorb light from the sun, and through a long process of chemical reactions convert that light energy into chemical energy. And so in this equation here we see that light plus water plus CO2 yields sugars and oxygen. Now the first step of that procedure is light plus water generates oxygen and four protons and four electrons. In this process there's basically a complex enzymatic reaction in which the water is cleaved into oxygen and hydrogen ions and electrons are released. Now, if we look at the oxidation states of oxygen in both water and, and the diatomic oxygen molecule we see that in its state of water oxygen has a oxidation state of minus two, and each of the hydrogens have an oxidation state of plus one. In molecular oxygen the oxidation state is zero. So by rule, we've gone from an oxidation state of negative two to zero, the oxidation state has increased and therefor ox, or water is being oxidized in this reaction. I'm Dan Weisenberger, and this is during photosynthesis is water oxidized or reduced.