Like mitochondria, chloroplasts are also distinctive organelles of eucaryotic cell. But they are found only in plant cells. Chloroplasts contain membranes forming a system of thin srs or larnellae stacked on top of each other. These membranes contain the pigment chlorophyll whose function is to trap light energy required to make organic molecules particularly sugars. This process is called photosynthesis. It is worth mentioning that chloroplasts resemble the present day cyanobacteria in size and structural organisation of chlorophyll bearing membranes. Chloroplasts also contain DNA and reproduce by self-replication. In fact a number of present day eucaryotic cells do contain cyanobacteria in them (Figure shown below).