Photorespiration

The site for photorespiration is chloroplast. Peroxisome and mitochondrion are required for completing the process. At high temperature, RuBP carboxylase functions as oxygenase and instead of fixing carbon dioxide, oxidises ribulose 1, 5-biphosphate to produce a 3-carbon phosphoglyceric acid and a 2-carbon phosphoglycolate. It is the first reaction of photorespiration. Phosphoglyceric acid or PGA is used up in Calvin cycle. Phosphoglycolate is hydrolysed (dephosphorylated) to form glycolate. Glycolate usually passes into peroxisome of the mesophyll cell where it is oxidised to glyoxylate