Question
Question: If \[9ATP\] and \[6NADPH\] are utilized for photosynthetic carbon assimilation through the Calvin cy...
If 9ATP and 6NADPH are utilized for photosynthetic carbon assimilation through the Calvin cycle, what would be the ratio of erythrose4- phosphate, xylulose5- phosphate, and ribulose 5- phosphate molecules formed as intermediates in the regeneration phase of the Calvin cycle?
A. 3:1:2
B. 2:2:1
C. 2:3:1
D. 1:2:3
Solution
The photosynthesis in prokaryotes occurs by two general methods- light-dependent reactions and the Calvin cycle, which initiates in the chloroplasts.
You may have seen that the general response for photosynthesis:
6CO2+6H2O→C6H12O6+6O2
is the converse of the general response for cell respiration:
6O2+C6H12O6→6CO2+6H2O
Photosynthesis produces oxygen as a result, and respiration produces carbon dioxide as a side-effect.
Complete answer:
The regeneration stage can be separated into steps.
Triosephosphate isomerase changes over the entirety of the G3P reversibly into dihydroxyacetone phosphate (DHAP), additionally a 3-carbon atom.
Aldolaseandfructose−1,6−bisphosphatase convert a G3P and a DHAP into fructose 6 -phosphate (6C). A phosphate particle is lost into the arrangement.
At that point, the fixation of another CO2 creates two more G3P.
F6P has two carbons eliminated by transketolase, giving erythrose-4 phosphate. The two carbons on transketolase are added to a G3P, giving the ketose xylulose- 5 -phosphate (Xu5P).
E4P and a DHAP (framed from one of the G3Pfrom the subsequent CO2 fixation) are changed over into sedoheptulose−1,7−bisphosphate (7C) by aldolase protein.
Sedoheptulose−1,7−bisphosphatase (one of just three proteins of the Calvin cycle that are extraordinary to plants) cuts sedoheptulose−1,7−bisphosphate into sedoheptulose-7-phosphate, delivering an inorganic phosphate particle into the arrangement.
Regeneration of a third CO2
Creates two more G3P. The ketose S7P has two carbons eliminated by transketolase, giving ribose-5-phosphate (R5P), and the two carbons staying on transketolase are moved to one of the G3P, giving another Xu5P. This leaves one G3P due to an obsession of 3 CO2, with the age of three pentoses that can be changed over to Ru5P.
R5P is changed over into ribulose-5-phosphate (Ru5P, RuP) by phosphopeptide isomerase. Xu5P is changed over into RuP by phosphopentose epimerase.
Finally, phosphoribulokinase (another plant-interesting chemical of the pathway) phosphorylates RuP into RuBP, ribulose−1,5−bisphosphate, finishing the Calvin cycle. This requires the contribution of one ATP.
Hence, the correct answer is option (D).
Note: Utilizing the energy transporters framed in the primary phase of photosynthesis, the Calvin cycle responses fix CO2from the climate to assemble starch particles. A compound, RuBisCO, catalyzes the obsession response by joining CO2 with RuBP. The subsequent six-carbon mixture is separated into two three-carbon mixes, and the energy in ATP and NADPH is utilized to change over these atoms into G3P.
Plants are equipped for both photosynthesis and cell respiration since they contain the two chloroplasts and mitochondria.