Chloroplasts are found in plant cells and some algae. These organelles are responsible for photosynthesis, the process by which light energy is converted into chemical energy to fuel the plant’s activities. Chloroplasts contain a green pigment called chlorophyll, which captures light energy.
In plant cells, chloroplasts are typically located in the mesophyll cells of leaves. They are also present in other green parts of the plant, such as stems and unripe fruits. The presence of chloroplasts is one of the key features that distinguish plant cells from animal cells, as animal cells do not contain chloroplasts.
Chloroplasts have their own DNA and ribosomes, which suggests they originated from free-living photosynthetic bacteria that were engulfed by a host cell in a symbiotic relationship. This theory is known as the endosymbiotic theory.