When this happens, the isolated chloroplasts will start creating ATP. Take note that ATP together with NADPH is usually needed in order to create photosynthetic cells. ATP is very important in the process of creating organic molecules from carbon dioxide and water that plants have access to.
Take note that ATP should be broken down further into ADP and then phosphate. This explains why ATP does not last for a long time. This can always have to be changed. These will be used by the plants in order to thrive more.