Question

The most abundant enzyme of the world is related to all, except __________.
A.Heat sensitivity
B.Photorespiration
C.Have much greater affinity for ${O_2}$than $C{0_2}$ when $C{O_2}:{O_2}$ is nearly equal
D.Have $M{g^{2 + }}$ as its activator

Answer 1

The only enzyme capable of catalyzing the net fixation of inorganic carbon dioxide into an organic form. It is majorly involved in the light-independent phase or dark phase of photosynthesis.

Complete answer: Ribulose-1,5-bisphosphate carboxylase oxygenase is a copper-containing enzyme that is involved in the first step of carbon fixation of the Calvin cycle. It is the most abundant protein on the earth and is the central enzyme of photosynthesis. It evolved about 3.6 billion years ago. It helps in fixing inorganic carbon to organic form. It has many small subunits and large units. It is commonly found in cyanobacteria, algae, and plants. It is located in the stroma of chloroplast in algae and plants. The active sites of this enzyme are located in the large subunits and the small subunits have different functions. It is involved in the light-independent reactions or the dark phase of photosynthesis. It catalyzes the reaction of carbon dioxide with ribulose-1,5-biphosphate to form two molecules of 3-Phosphoglycerate.
It binds to carbon dioxide when it is present in high concentration and it binds to oxygen when it is present in high concentration. When it binds to oxygen then, it helps in photorespiration.
Hence, the correct option is A) Heat sensitivity.

Note: Heat stress inhibits the process of photosynthesis by reducing the activation of RuBisCO by another enzyme RuBisCO activase. RuBisCO activase is extremely heat sensitive and is inactivated at higher temperatures which leads to the inactivation of RuBisCO.