Final answer:
The light reactions of photosynthesis provide the Calvin cycle with ATP and NADPH, which are used to convert atmospheric carbon dioxide into glucose and other carbohydrates.
Step-by-step explanation:
The light reactions of photosynthesis supply the Calvin cycle with ATP and NADPH. These molecules are the energy carriers that fuel the Calvin cycle reactions. During the light-dependent reactions, energy from sunlight is harnessed in the thylakoid membranes of the chloroplasts, which leads to the production of ATP and NADPH. These compounds are then utilized in the Calvin cycle, also known as the light-independent reactions, where carbon dioxide from the atmosphere is 'fixed' into organic sugar molecules, primarily glucose.
The Calvin cycle consists of two parts. Initially, carbon dioxide is fixed by an enzyme called RuBisCO in a reaction with a molecule called ribulose biphosphate (RuBP). Subsequently, the Calvin cycle uses the chemical energy from ATP and the reducing power of NADPH to convert the fixed carbon into glucose. After a series of reactions, for every three turns of the cycle, one molecule of a three-carbon sugar, glyceraldehyde-3-phosphate (G3P), is produced, which is then used to build glucose and other carbohydrates.