Question

Explain i) the reason why photorespiration occurs ii) how the extent of global photorespiration changes with global warming, iii) describe two distinct aspects on how photorespiration can adversely impact life on the planet

Answer 1

Explanation:

1.

Photorespiration is a metabolic pathway that mostly occurs during the daytime in the C3 plants, during high environmental temperature, ribulose bi-phosphate attaches with oxygen a rather than atmospheric CO₂ & converted to two carbon compound (glycolate), instead of fixation of CO₂ during the C3 cycle. The glycolate enters into peroxisomes & mitochondria as glycolate pathway and finally returns the chloroplast without generating ATPs . Hence photorespiration leads to significant photosynthetic loss in C3 plants .

2.

At present time global extent of photorespiration is increasing due to enhancement of global warming effects. Since, increased atmospheric temperature would decrease the ribulose biphosphate affinity to carbon dioxide but increases with the oxygen, which significantly affect the photosynthetic rate in C3 plants.

3.

Since, it decreases the photosynthetic rate in C3 plants, the fixation of CO₂during Calvin cycle would be compromised and leads to increment of CO₂ concentration above the certain limited range, finally causes harmful green house effects on the living organisms. Due to utilisation of O₂ in photorespiration pathway, the concentration of oxygen would also dropped down slowly in atmosphere in any way. However, photorespiration has some beneficial effects on C3 plants, since it protects them from light induced damage to the molecule used in photosynthesis process.