A chloroplast is an organelle unique to plant cells that contains chlorophyll (which is what makes plants green) and is responsible for enabling photosynthesis to occur, so that plants can convert sunlight into chemical energy. So basically, without chloroplasts, plants could not create energy, and without them, humans would have no food and we would perish, so thank you chloroplasts!
The function of chloroplasts is to convert sunlight, water and carbon dioxide into food for the plant. Chloroplasts are energy organelles, and are present in all types of plants.