Which cycle occurs in the stroma of the chloroplast, converting carbon dioxide into carbohydrates?

The Calvin cycle occurs in the stroma of the chloroplast and is crucial for the process of photosynthesis. This cycle utilizes carbon dioxide from the atmosphere and, through a series of enzymatic reactions, converts it into carbohydrates, primarily glucose.

During the Calvin cycle, carbon dioxide is fixed by an enzyme called ribulose bisphosphate carboxylase oxygenase (RuBisCO), leading to the formation of 3-phosphoglycerate (3-PGA). This molecule is then reduced using ATP and NADPH produced in the light-dependent reactions of photosynthesis. Through a series of reactions, these molecules are ultimately transformed into carbohydrate compounds, storing energy that can later be used by the plant and, indirectly, by organisms that consume plants.

This process emphasizes the role of light energy converted to chemical energy in the form of ATP and NADPH, which fuels the synthesis of organic molecules in the Calvin cycle. Thus, the correct identification of the Calvin cycle clarifies its role in converting inorganic carbon dioxide into organic sugars, supporting life in ecosystems.