fotosinteza

Fotosinteza, also known as photosynthesis, is the process by which light energy is captured and stored as chemical energy in organic molecules, enabling the synthesis of carbohydrates from carbon dioxide and water. In most organisms that perform photosynthesis, oxygen is released as a byproduct. The general equation can be summarized as CO2 + H2O + light energy -> (CH2O)n + O2.

Most photosynthesis occurs in chloroplasts in plant cells and algal cells, which contain chlorophyll and other pigments. The process has two main stages: light-dependent reactions and the Calvin cycle (also called the light-independent reactions). The light-dependent reactions occur in the thylakoid membranes and convert light energy into ATP and NADPH, releasing oxygen from water. The Calvin cycle uses ATP and NADPH to fix CO2 into sugars in the stroma.

Organisms that perform photosynthesis include plants, algae, and cyanobacteria. Some bacteria perform anoxygenic photosynthesis that does not release oxygen. Photosynthesis is central to life on Earth, providing the primary source of organic matter for almost all organisms and driving the atmospheric oxygen balance and the global carbon cycle. Environmental factors such as light intensity, carbon dioxide concentration, temperature, and water availability influence the rate of photosynthesis. Plants have evolved adaptations such as C4 and CAM pathways to optimize efficiency under different conditions.

Modern research also covers the regulation of photosynthetic apparatus, photoprotection mechanisms to prevent damage from excess light, and the potential for improving crop yields and bioenergy through genetic and agronomic approaches.

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