What is the main role of chloroplasts in plant cells?

Chloroplasts are specialized organelles found in plant cells that play a crucial role in the process of photosynthesis. Their primary function is to convert light energy, typically from the sun, into chemical energy in the form of glucose, a carbohydrate. This process also produces oxygen as a byproduct.

During photosynthesis, chloroplasts capture sunlight using chlorophyll, the green pigment in the chloroplasts. This light energy is then harnessed to convert carbon dioxide and water, which are absorbed by the plant, into glucose through a series of biochemical reactions. The glucose produced serves as an essential energy source for the plant, supporting growth and development, and can be stored for later use or used in various metabolic processes.

The other choices relate to functions not performed by chloroplasts: water storage is primarily managed by vacuoles in plant cells, cellular respiration occurs in mitochondria, and protein modification takes place in the endoplasmic reticulum and Golgi apparatus. Therefore, the correct choice highlights the unique and vital role of chloroplasts in the synthesis of carbohydrates through photosynthesis.