Question

Does photorespiration Release $C{O}_2$?

Answer 1

Photorespiration:

1. In many higher plants, a respiratory process occurs in which they take in oxygen from the light and release some carbon dioxide, in contrast to the general pattern of photosynthesis.
2. This process does not produce ATP or NADPH and is a wasteful process.
3. The gas exchange resembles respiration and is the reverse of photosynthesis.

Release of $C{O}_2$ during photorespiration:

1. Photorespiration is a process which involves loss of fixed carbon as ${\mathrm{CO}}_2$ ​and taking in molecular oxygen $\left(O_2\right)$ in plants in the presence of light. It is initiated in chloroplasts.
2. Photorespiration occurs usually when there is the high concentration of oxygen.
3. Under such circumstances, RuBisCO, the enzyme that catalyses the carboxylation of RuBP during the first step of Calvin cycle, functions as an oxygenase.
4. Some ${\mathrm{O}}_2$ ​does bind to RuBisCO and hence ${\mathrm{CO}}_2$ ​fixation is decreased.
5. The RuBP binds with ${\mathrm{O}}_2$ ​to form one molecule of PGA (3C compound) and phosphoglycolate (2C compound) in the pathway of photorespiration.
6. There is neither the synthesis sugar nor of ATP.