The cell would die. This is because mitochondria are essential for making energy that the cell can use, if the mitochondria stopped working this energy would not longer be available to the cell. If the cell does not have energy, it cannot perform vital functions like respiration.
Plants use carbon dioxide in a process known as photosynthesis. During photosynthesis, plants give off oxygen as a waste product. Carbon dioxide moves from the air into the leaves of plants through tiny openings in the plant's leaves. Oxygen moves out of the plant leaf through these same openings.