What Makes the Light Reactions So Important ?
• Two actions of great consequence take place in the light reactions. The first action is that water is split, yielding both the electrons that move through the light reactions and the oxygen that organisms such as ourselves breathe in. The second action is that the electrons that are given an energy boost in the light reactions don t simply release heat or light, as is common in such energizing; instead, they are transferred to a different molecule, the initial electron acceptor. This is one of the keys to the plant s ability to make its own food. The energetic fall of electrons through the electron transport chain between photosystems II and I also yields energy that produces ATP, which is used to power the second stage of photosynthesis. Back to the Top 8.5 Stage 2 of Photosynthesis: The Calvin Cycle • In the second stage of photosynthesis, carbon dioxide from the atmosphere is brought together with a sugar, RuBP, by the enzyme rubisco. The resulting compound is energized with the a
