Chloroplasts are the site of photosynthesis in plant cells. They contain chlorophyll, a pigment that absorbs light energy from the sun and converts it into chemical energy. This energy is then used to produce glucose, a sugar molecule that plants use for energy.
In a school, the chloroplast can be compared to the cafeteria. The cafeteria is where students go to get food, which gives them energy. Just like the chloroplasts produce food for the plant, the cafeteria provides food for the students.