Primary CO2 Acceptor and First Stable Product
Identification of Ribulose-1,5-bisphosphate (RuBP) as the CO2 acceptor and 3-Phosphoglyceric acid (PGA) as the first stable 3-carbon product.
What is Primary CO2 Acceptor and First Stable Product?
A five-carbon sugar molecule that acts as the primary carbon dioxide acceptor in the Calvin cycle of photosynthesis.
Key points
- Identify the primary CO2 acceptor in the Calvin cycle.
- Identify the first stable product of carbon fixation in the Calvin cycle.
- Understand the role of RuBisCO in the initial step.
- Recognize the carbon number of RuBP and PGA.
Common exam trap
Confusing RuBP with the product (PGA).
Definitions
- Term
Ribulose-1,5-bisphosphate (RuBP)
- Meaning
A five-carbon sugar molecule that acts as the primary carbon dioxide acceptor in the Calvin cycle of photosynthesis.
- Term
3-Phosphoglyceric acid (PGA)
- Meaning
A three-carbon molecule that is the first stable product of carbon fixation in the Calvin cycle.
- Term
RuBisCO
- Meaning
Ribulose-1,5-bisphosphate carboxylase/oxygenase, the enzyme that catalyzes the first step of carbon fixation in the Calvin cycle.
Learning objectives
Identify the primary CO2 acceptor in the Calvin cycle.
Identify the first stable product of carbon fixation in the Calvin cycle.
Understand the role of RuBisCO in the initial step.
Recognize the carbon number of RuBP and PGA.
Prerequisites
Photosynthesis: Light-dependent reactions
Chloroplast structure and function
Enzyme action
Common mistakes
Confusing RuBP with the product (PGA).
Forgetting the number of carbon atoms in RuBP (5) and PGA (3).
Misidentifying the enzyme RuBisCO.
Not understanding the role of ATP and NADPH in the cycle.
Keywords
Calvin Cycle
C3 Pathway
Carbon Fixation
RuBP
PGA
RuBisCO
Photosynthesis
Chloroplast
Stroma
Practice preview
Consider the initial carboxylation event in the Calvin cycle. If a plant were to experience a severe deficiency in atmospheric CO2, which molecule's concentration would likely decrease significantly due to its role as th…
hard
In the Calvin cycle, what is the primary CO2 acceptor molecule?…
easy
What is the first stable product formed during the Calvin cycle (C3 pathway)?…
easy