Photosynthesis is a biological process where organisms convert light energy into chemical energy, using carbon dioxide and water to produce glucose and oxygen. It involves two main stages: light-dependent reactions and light-independent reactions (Calvin cycle).
1. Light-Dependent Reactions:
Light Absorption:
Chlorophyll, the primary pigment in plants, absorbs sunlight, mainly in the red and blue wavelengths.
Water Splitting:
Water molecules are split, releasing oxygen as a byproduct, electrons, and protons.
Electron Transport:
Electrons move through a series of protein complexes, releasing energy which is used to create ATP (adenosine triphosphate) and NADPH (nicotinamide adenine dinucleotide phosphate).
2. Light-Independent Reactions (Calvin Cycle):
Carbon Dioxide Fixation: Carbon dioxide from the atmosphere is incorporated into organic molecules, starting with ribulose-1,5-bisphosphate (RuBP).
Sugar Formation: NADPH and ATP, produced during the light-dependent reactions, are used to convert the fixed carbon dioxide into glucose.
RuBP Regeneration: The cycle continues, regenerating RuBP to keep the process going.