Photosynteesiprosessit

Photosynteesiprosessit refers to the biological processes by which green plants, algae, and cyanobacteria convert light energy into chemical energy. This chemical energy is stored in carbohydrate molecules, such as sugars, which are synthesized from carbon dioxide and water. Photosynthesis is crucial for life on Earth as it produces the oxygen we breathe and forms the base of most food chains.

There are two main stages in photosynthesis: the light-dependent reactions and the light-independent reactions (also known as the Calvin cycle). The light-dependent reactions occur in the thylakoid membranes of chloroplasts. Here, chlorophyll and other pigments capture light energy, which is used to split water molecules. This process releases electrons, protons, and oxygen as a byproduct. The energy from light is also used to generate ATP and NADPH, energy-carrying molecules.

The light-independent reactions take place in the stroma of the chloroplasts. These reactions do not directly require light but utilize the ATP and NADPH produced during the light-dependent reactions. In the Calvin cycle, carbon dioxide from the atmosphere is "fixed" and incorporated into organic molecules. Through a series of enzymatic reactions, this fixed carbon is converted into glucose and other carbohydrates. These sugars can then be used by the organism for energy or as building blocks for growth. The overall equation for photosynthesis is often summarized as 6CO2 + 6H2O + Light Energy → C6H12O6 + 6O2.