Which is a primary function of chloroplasts?

Chloroplasts are specialized organelles found in plant cells and some protists, and their primary function is photosynthesis. During this process, chloroplasts capture light energy from the sun and convert it into chemical energy in the form of glucose. This is accomplished through two main stages: the light-dependent reactions and the light-independent reactions (Calvin cycle). In the light-dependent reactions, chlorophyll within chloroplasts absorbs sunlight and uses that energy to split water molecules, releasing oxygen and generating energy-rich molecules like ATP and NADPH. The Calvin cycle then uses these energy carriers along with carbon dioxide from the atmosphere to produce glucose, which serves as an essential energy source for the plant and, ultimately, for other organisms in the food chain. This makes photosynthesis a vital process not only for the plants but also for life on Earth as a whole, because it is the foundation of the food web and oxygen production.