The Calvin cycle is a series of chemical reactions that takes place in chloroplasts of cells of photosynthetic organisms. The Calvin
cycle is driven by chemical energy that is produced in the light reactions of photosynthesis. What occurs during the Calvin cycle?
A.
complex carbohydrates are broken down to produce energy
B. simple sugars are formed from carbon dioxide
C. complex carbohydrates are broken down to form simple sugars
D. simple sugars are formed from oxygen

During the Calvin cycle, which occurs in the chloroplasts of photosynthetic organisms, simple sugars are formed from carbon dioxide (option B).

Explanation:

The Calvin cycle is part of the process of photosynthesis - although is often called the light-independent process - being a mechanism of incorporation of carbon dioxide (CO₂) to become organic matter by plants and other organisms endowed with chloroplasts.

The plant cell takes the CO₂ from the environment and incorporates it into the chloroplast where -in presence of NADPH and energy (ATP)- 6 molecules of CO₂ become 1 molecule of glucose, a process mediated by the enzyme ribulose-1,5-bisphosphate carboxylase / oxygenase (RuBisCO).

In this way, the photosynthetic organism is capable of transforming inorganic molecules, such as CO₂, into organic matter, as a simple sugar.

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Calvin cycle link