Question
Biology Question on Calvin cycle
The primary acceptor, during CO2 fixation in C3 plants, is
A
phosphoenolpyruvate (PEP)
B
ribulose 1, 5-diphosphate (RuDP)
C
phosphoglyceric acid (PGA)
D
ribulose monophosphate (RMP).
Answer
ribulose 1, 5-diphosphate (RuDP)
Explanation
Solution
The Calvin cycle is also known as C3 cycle because CO2, reduction is cyclic process and first stable product in this cycle is a 3-C compound (i.e., 3-phosphoglyceric acid or 3-PGA). In this cycle, CO2 acceptor molecule is RuBP or RuDP (i.e., Ribulose 1, 5-biphosphate or Ribulose 1, 5-diphosphate). There occurs covalent bonding of CO2, to RuBP and the enzyme catalyzing this reaction is RuBP-carboxylase/oxygenase (RuBisCO).