Answer:
The primary function of the Calvin cycle is to produce glucose from carbon dioxide.
The Calvin cycle, also known as the Calvin-Benson cycle or the dark reactions of photosynthesis, is a series of biochemical redox reactions that take place in the stroma of chloroplast in photosynthetic organisms. It was discovered by Melvin Calvin, James Bassham, and Andrew Benson at the University of California, Berkeley.
The Calvin cycle has three stages: carbon fixation, reduction, and regeneration of ribulose 1,5-bisphosphate (RuBP).
1. Carbon Fixation: The enzyme RuBisCO catalyzes the carboxylation of RuBP to form a six-carbon intermediate which immediately splits into two molecules of 3-phosphoglycerate (3-PGA).
2. Reduction: ATP and NADPH from the light-dependent reactions are used to convert 3-PGA into glyceraldehyde 3-phosphate (G3P). This is a two-step process that includes phosphorylation (using ATP) and reduction (using NADPH).
3. Regeneration of RuBP: The majority of G3P produced in the second stage is used to regenerate RuBP so that the cycle can continue.
For every three molecules of CO2 that enter the cycle, one molecule of glucose is formed. This is because each CO2 molecule produces one G3P molecule, but it takes two G3P molecules to make one glucose molecule.