Question

Under what conditions RuBP behaves as a Carboxylase
and oxygenase?​

Answer 1

Answer:

RuBisCO stands for Ribulose Bisphosphate Carboxylase Oxygenase. It is formed from Ribulose bisphosphate (RuBP)- a five-carbon ketose sugar. ... It has a great affinity for CO2 and O2 and the binding is competitive. This shift in roles occurs when the concentration of either CO2 or O2 increases

Answer 2

1. RUBP act as carboxylase in presence of more carbon dioxide and act as oxygenase when CO2 level is low, O2 level is high and at high temperature
2. RUBP carboxylase is used in calvin cycle for formation of PGA ( Phosphoglyceric acid)
3. When CO2 level is low and temperature is high RUBP carboxylase act as oxygenase and bring about oxidation instead of carboxylation
4. This process is called photorespiration and took place in C3 Plants
5. RUBP i.e. Ribulose Bis Phosphate, act as a main role in photosynthesis of plants
6. The process of respiration that is initiated in plants and only during day is called Photorespiration
7. At high temperature, High light concentration and low CO2 concentration oxidation of RUBP ( RUBP oxygenase) by oxygen take place which result in C2 cycle or photorespiration
8. In photorespiration, one molecule of 2 C compound phosphoglycolate and one molecule of PGA is formed
9. In C4 plants photorespiration is avoided due to C4 pathway because of that they never undergo C2 cycle
10. Due to formation of RUBP oxygenase, 25% of photosynthetically fixed CO2 goes back to atmosphere which is a major loss to plants. This is what we call Photorespiration or C2 cycle or formation of RUBP oxygenase