What is the primary function of chloroplasts within plant cells?

The primary function of chloroplasts within plant cells is photosynthesis. Chloroplasts are specialized organelles that contain chlorophyll, the pigment responsible for capturing light energy from the sun. During the photosynthesis process, chloroplasts convert this light energy into chemical energy in the form of glucose by utilizing carbon dioxide from the atmosphere and water from the soil. This process not only produces glucose, which serves as food for the plant, but also releases oxygen as a byproduct, essential for many living organisms.

While chloroplasts do play a role in the synthesis of starch as a storage form of glucose, this is part of the larger photosynthetic process. The other functions listed, such as protein export and cell division, are primarily associated with different organelles within the cell. For example, ribosomes and the endoplasmic reticulum are responsible for protein synthesis and export, while the nucleus and centrosomes play roles in cell division.