The part labelled I in the diagram is the chloroplast. Chloroplasts are specialized organelles found in plant cells that contain chlorophyll, a green pigment that absorbs light energy from the sun during the process of photosynthesis. They are responsible for the conversion of light energy into chemical energy, which is used by the plant to produce food (glucose) and release oxygen. Chloroplasts are usually located in the mesophyll layer of the leaf and are green in color due to the presence of chlorophyll.
