Chloroplast has many jobs that it must perform. It works with the nucleus, membrane, and ER as a pathogen defense. Though that is one of its jobs, the most important job it has is to make food by the process of photosynthesis. Food is prepared in the form of sugars. During photosynthesis, sugar and oxygen are made using water, CO2, and light eneregy. This is the chloroplast’s most important job because if plants can’t go through photosynthesis, they won’t be able to convert CO2 to oxygen which would mean that humans wouldn’t have oxygen to breathe. The chloroplast is only found in plant cells and algae. They are not in prokaryots.