The Calvin Cycle is a crucial part of photosynthesis, the process by which plants convert sunlight into energy. It takes place in the chloroplasts of plant cells and uses carbon dioxide from the air. During this cycle, energy from ATP and NADPH, produced in the light-dependent reactions, helps convert carbon dioxide into glucose, a sugar that plants use for energy and growth. This cycle consists of three main stages: carbon fixation, reduction, and regeneration. In the first stage, carbon dioxide is combined with a five-carbon sugar called ribulose bisphosphate (RuBP). The resulting compound is then transformed through a series of reactions, ultimately regenerating RuBP to continue the cycle.