What are the three phases of the Calvin cycle?

The three phases of the Calvin cycle are carbon fixation, the reduction phase, and the regeneration of RuBP.

In the carbon fixation phase, carbon dioxide from the atmosphere is incorporated into an organic molecule, which is facilitated by the enzyme RuBisCO. This step is crucial as it transforms inorganic carbon into a form that can be used by living organisms.

The reduction phase follows, where the fixed carbon undergoes a series of reactions that convert it into glyceraldehyde-3-phosphate (G3P), a three-carbon sugar. This phase utilizes ATP and NADPH generated during the light-dependent reactions of photosynthesis, facilitating the transformation of the fixed carbon into an energy-rich form.

Finally, the regeneration of RuBP (ribulose bisphosphate) is vital for the cycle to continue. In this phase, some of the G3P molecules produced are used to regenerate RuBP, allowing the cycle to restart and continue processing additional carbon dioxide.

The accuracy of this pathway highlights the importance of the Calvin cycle in converting carbon into usable energy forms, distinguishing it clearly from unrelated processes such as glucose synthesis or stages of light reaction and cellular respiration.