Final answer:
The Calvin cycle is a part of photosynthesis that converts atmospheric CO2 into carbohydrates. It involves carbon fixation by the enzyme RuBisCO, followed by the reduction of fixed carbon using ATP and NADPH to form sugars, and ends with the regeneration of RuBP.
Step-by-step explanation:
The Calvin cycle, also known as the light-independent reactions of photosynthesis, accomplishes the carbon fixation of inorganic CO₂ gas from the atmosphere into organic compounds. The cycle can be divided into three stages: fixation, reduction, and regeneration. In the fixation stage, an enzyme called ribulose biphosphate carboxylase (RuBisCO) catalyzes the reaction of CO₂ with ribulose bisphosphate (RuBP). This process initiates the transformation of CO₂ into more complex organic molecules. Subsequently, in the reduction phase, the energy stored in ATP and the reducing power of NADPH, both products of the light-dependent reactions of photosynthesis, are used to convert these fixed carbons into sugars like glucose. In the final regeneration phase, the remaining molecules are converted back into RuBP, allowing the cycle to perpetuate. Thus, the Calvin cycle plays a critical role in transforming carbon from its inorganic form into vital organic compounds that are used by the plant to produce energy and biomass.