Thoughts and Suggestions for Cellular Energetics...Photosynthesis

I recognize that Cellular energetics was quite the wild ride for you guys. Based on the results of the recent Cellular Respiration test you took, I believe that you need to wade back into it some more on your own to be sure you really understand and grasp how Cellular Respiration is conducted and how it connects to Photosynthesis. Remember, the two processes are linked in a great cycle, and if you stop one long enough, the other will stop as well. The reactants and the products are the links that tie these two together, so let's quickly touch on that before I recommend some sites to review with. We'll start with Photosynthesis in this post.

Remember that Photosynthesis is a two stage process. The light dependent reaction is essential for creating energy for the second stage. The light dependent reaction converts solar energy into chemical energy in the form of NADPH+ and ATP. It does this through the use of light capturing pigments, and the movement of excited electrons through the electron transport chain embedded in the membrane of the thylakoids.  These two sources of energy are going to move into the open space in the Chloroplast, the Stroma, to power up the Calvin Cycle - the sugar production phase.

 The Calvin Cycle occurs in the open stroma of the Chloroplast, and is the site of Carbon Fixation. Carbon Dioxide (CO2) is taken in through the stomates of the plant and moves to the chloroplasts, where it is captured by a molecule of that ever prevalent 5 Carbon molecule of Rubisco. This new 6-Carbon molecule will be split into two 3-Carbon molecules, which are molecules reduced using the energy carried by the NADPH+ and ATP into G3P. One of these molecules of G3P will be used as a building block for Glucose, while the other G3P will combine with the 2-C remains to form a regenerated molecule of Rubisco. It will take 6 cycles of this process to make one Glucose molecule.

In the earliest stages of Photosynthesis, H20 is split to free up electrons needed for the electron transport chain and to create a Proton gradient to drive ATP synthase. The Oxygen will be released as that happy byproduct needed by most cells for respiration. The electrons will move on down the road on the ETC. The Oxygen will reappear as the reactant in the next system: Cellular Respiration. Thus the cycles are linked and you should be able to describe the inputs and outputs of both stages.