During dark reaction for fixation of carbon, where are the three carbon atoms of each molecule of 3-PGA derived from?

Question

During dark reaction for fixation of carbon, where are the three carbon atoms of each molecule of 3-PGA derived from? (A) RuBP only (B) RuBP+CO2 (C) CO2 only (D) RuBP+CO2+PEP

Tardigrade Admin · Accepted Answer

The Calvin cycle or C3 cycle or dark cycle occurs in all photosynthetic plants. It is divided into 3 stages. The first stage is Carboxylation. Carboxylation is the fixation of CO2 into a stable organic intermediate. In this, CO2 is utilized for the carboxylation of RuBP. This reaction is catalyzed by the enzyme RuBisCo and it results in the formation of 2 molecules of 3-PGA (3-Phosphoglyceric acid).

Q. During dark reaction for fixation of carbon, where are the three carbon atoms of each molecule of $3 - PG A$ derived from?

$R u BP$ only

$R u BP + C O_{2}$

$C O_{2}$ only

$R u BP + C O_{2} + PEP$

Q. During dark reaction for fixation of carbon, where are the three carbon atoms of each molecule of 3−PGA derived from?

RuBP only

RuBP+CO2​

CO2​ only

RuBP+CO2​+PEP

Q. During dark reaction for fixation of carbon, where are the three carbon atoms of each molecule of $3 - PG A$ derived from?

$R u BP$ only

$R u BP + C O_{2}$

$C O_{2}$ only

$R u BP + C O_{2} + PEP$