What term describes the part of photosynthesis that occurs in the stroma of chloroplasts?

The process of photosynthesis that happens in the stroma of chloroplasts is accurately described by the term "light-independent reactions." This term refers specifically to the series of biochemical reactions that do not require light to occur directly. Instead, these reactions utilize the products of the light-dependent reactions, such as ATP and NADPH, generated in the thylakoid membranes.

In the light-independent reactions, carbon dioxide is fixed into organic molecules through a series of steps, ultimately leading to the synthesis of glucose and other carbohydrates. This set of reactions is often identified as the Calvin cycle, emphasizing its role in carbon fixation and sugar production. Therefore, it is also correct to refer to the light-independent reactions as the Calvin cycle, but the broader term encompasses all aspects of these reactions occurring in the stroma.

In summary, light-independent reactions, which include the Calvin cycle, are crucial for synthesizing organic compounds from carbon dioxide, leveraging the energy stored in ATP and NADPH. The distinction from light-dependent reactions, which occur in the thylakoid membranes and involve capturing light energy and producing energy carriers, further clarifies the roles of different phases of photosynthesis.