Significance of Photorespiration

Even though it represents a net loss of fixed carbon and energy, photorespiration is not simply wasteful - it delivers three genuine benefits to the plant. First, the glycine and serine synthesised as intermediates along the photorespiratory pathway are not dead ends; they serve as precursor molecules for several other essential biomolecules the plant needs, including chlorophyll, proteins and nucleotides. Second, the pathway consumes surplus NADH+H+ that would otherwise accumulate under the high-light conditions that trigger photorespiration in the first place, helping to keep the cell's redox balance in check. Third, the glycolate generated early in the pathway helps protect the cell against photo-oxidative damage, acting as something of a safety valve for excess reducing equivalents and reactive bypro …