1. Light Energy to Chemical Energy:
* Light-dependent reactions: This stage captures light energy from the sun.
* Pigments like chlorophyll absorb light energy.
* This energy excites electrons in the chlorophyll molecules.
* Excited electrons are passed along an electron transport chain, releasing energy.
* This energy is used to create ATP (adenosine triphosphate), the cell's energy currency.
* Water molecules are split, releasing oxygen as a byproduct.
2. Chemical Energy to Chemical Energy:
* Light-independent reactions (Calvin cycle): This stage uses the chemical energy stored in ATP and NADPH (another energy carrier) to convert carbon dioxide into glucose.
* Carbon dioxide from the atmosphere is incorporated into organic molecules.
* This process requires energy from ATP and reducing power from NADPH.
* Glucose, a sugar, is formed as the final product.
Overall:
The energy transformations in photosynthesis can be summarized as follows:
* Light energy from the sun is converted into chemical energy in the form of ATP and NADPH.
* This chemical energy is then used to convert carbon dioxide into glucose, storing chemical energy in the bonds of glucose.
In essence, photosynthesis takes light energy and transforms it into chemical energy in the form of glucose, a form that can be used by plants and other organisms for growth and other metabolic processes.
