Bacteria are tiny organisms made of one cell. Although they are too small to see with the human eye, most can be seen using a microscope. Bacteria can either be harmful or helpful. Bacteria are basically everywhere! They live in air, soil, and water. They are also considered as unicellular prokaryotic organisms.
A protist is any eukaryotic organism but it's not classified as a plant, animal or fungus. Protists are very special organisms because they don't find directly with the other groups. Protists may also contain mitochondria whereas bacteria do not have it. Also, bacteria does not contain chloroplasts but it's possible they can be found in certain types of protists.