What is the chemical relationship between the light dependent and the light independent (carbon fixation) reactions of photosynthesis? In what part of the chloroplast does each occur?
The light independent reaction occurs in the stroma of the chloroplast, and the light dependent reaction occurs in the thylakoid of the chloroplast. In the light dependent reaction (the two photosystems), products from there are transported to the light independent reaction. In the light dependent reaction, light (from the sun)splits two water molecules, and the H+ remains on the side, ready to be moved on to Photosystem I from II via the electron transport chain. Oxygen is released during Photosystem II. ATP synthase binds ADP and P together as the hydrogen atoms travel with the ATP synthase. In Photosystem I, NADP+ accepts and carries two pairs of hydrogen atoms, and while doing so, becomes NADPH. ATP and NADPH goes to the Calvin Cycle (light independent). In the Calvin Cycle, NADPH and ATP is taken in, and NADP+ and ADP is released to the light dependent reactions. Carbon dioxide is taken in, and glucose is released in the light independent reaction.
