Which of the following statements are true for photorespiration ?

Explanation

1. Photorespiration is a light dependent release of `CO_(2)` and uptake of `O_(2)` by the green tissue of particularly `C_(3)` plants. To understant photorespiration we must know first step in calvin cycle. In which RuBP combines to form 2 molecules of 3PGA that are catalysed by RuBiSCO.
2. RuBiSCO is the most abundant enzyme in the world. It has active site can bind to both `CO_(2) and O_(2)`. RuBiSCO has a much greater affinity for `CO_(2)` than `O_(2)`.
3. In `C_(3)` plants some `O_(2)` does bind to RuBiSCO and hence `CO_(2)` fixation is decreased. Here the RuBP, instead of being convert 2 molecules of PGA, binds with `O_(2)` to form one molecule of phosphoglycerate and phosphoglycolate in pathway called photorespiration.
4. In photorespiration there is no synthesis of ATP or NADPH & sugars. Therefore, photorespiration is a wasteful process.
5. In `C_(4)` plants photorespiration does not occur. This is because they have mechanism that increase the conc of `CO_(2)` at the enzyme site.