Photorespiration in $ {{C}_{3}}- $ plants starts from phosphoglycolate. Phosphoglycolate formed in chloroplast represents the source of carbon dioxide released in photorespiration. Its phosphate group is first hydrolyzed away by a specific phosphatase found in chloroplasts of $ {{C}_{3}}- $ plants releasing $ {{P}_{i}} $ and glycolic acid. The glycolate then moves out of chloroplasts into the adjacent peroxisomes.