Final answer:
ATP and NADPH, produced during the light-dependent reactions of photosynthesis, are necessary for the light-independent reactions to synthesize glucose from carbon dioxide.
Step-by-step explanation:
During photosynthesis, after the light-dependent reactions have taken place, the light-independent reactions, also known as the Calvin Cycle or dark reactions, commence. The substances needed for these light-independent reactions include carbon dioxide (CO₂), which enters the plant through the stomata, and the molecules ATP and NADPH, which are produced during the light-dependent reactions. These energy-carrying molecules are crucial as they provide the necessary chemical energy and electrons for the process of carbon fixation, where CO₂ is converted into organic sugar molecules, such as glucose.
The light-independent reactions do not directly require light to proceed and can occur both day and night as long as ATP and NADPH are available. The chemical energy stored in ATP and NADPH is used to bond the carbon atoms from CO₂ into glucose, which serves as a form of long-term energy storage for the plant.