Final answer:
Chloroplasts are located in the mesophyll of plant leaves and contain many chloroplasts for photosynthesis, where chlorophyll within thylakoid membranes captures light energy to produce glucose.
Step-by-step explanation:
Chloroplast-containing cells are primarily located in the mesophyll of plant leaves. These cells contain many chloroplasts because chloroplasts are the site of photosynthesis, a process in which plants convert light energy into chemical energy in the form of glucose. Chloroplasts have a double membrane envelope, with an inner and outer layer, and within the chloroplast are stacked, disc-shaped structures called thylakoids. It is within the thylakoid membranes that chlorophyll, the green pigment responsible for capturing light energy, is situated. The high concentration of chloroplasts in this tissue allows plants to maximize their ability to convert light energy into glucose and produce food through photosynthesis.