fotorespiraatioon

Fotorespiraatio is a metabolic process that occurs in plants, algae, and cyanobacteria, specifically in those that perform oxygenic photosynthesis. It is a light-dependent process that competes with carbon fixation during photosynthesis. Fotorespiraatio begins when the enzyme RuBisCO, which is responsible for capturing carbon dioxide for photosynthesis, mistakenly binds with oxygen instead of carbon dioxide. This oxygenation event initiates a complex series of reactions that consume oxygen and ATP, and release carbon dioxide. While it can lead to a loss of fixed carbon and energy, fotorespiraatio also plays a role in photoprotection by dissipating excess light energy under certain stress conditions. It is particularly prevalent in C3 plants when temperatures are high, light intensity is strong, and carbon dioxide levels are low. The process involves several organelles, including chloroplasts, peroxisomes, and mitochondria. Despite its apparent inefficiency in terms of carbon gain, evolution has retained fotorespiraatio, suggesting it confers some advantages, such as preventing photooxidative damage to the photosynthetic apparatus.