Besides carboxylation, the Calvin Cycle enzyme rubisco can also react with O2 (e.g. oxygenation). The wasteful oxygenation reaction of rubisco is explained by the enzyme developing at time when there was very little O2 in the atmosphere. Since it was developed, why hasn’t rubisco evolved to get rid of the oxygenation reaction?
Besides carboxylation, the Calvin Cycle enzyme rubisco can also react with O2 (e.g. oxygenation). The wasteful oxygenation reaction of rubisco is explained by the enzyme developing at time when there was very little O2 in the atmosphere.
Since it was developed, why hasn’t rubisco evolved to get rid of the oxygenation reaction?
-
A.
Mutations that decrease the affinity of rubisco for O2 probably also decrease the enzyme’s ability to bind CO2.
-
B.
Evolution takes time; and since rubisco is found only in eukaryotes, it evolved recently.
-
C.
Since it still generates one molecule of 3-phosphoglycerate (PGA), the oxygenation reaction is actually not that wasteful.
-
D.
Because in the past few million years the concentration of CO2 in the atmosphere has risen to be much greater than the concentration of O2.
Trending now
This is a popular solution!
Step by step
Solved in 2 steps
