Protists are organisms that are part of the biological kingdom called the protista. These organisms are not plants, animals, bacteria, or fungi.Protists are a very diverse group of organisms. They are basically all the organisms that don't fit into the other groups.ne major type of protist is algae. Algae are protists that perform photosynthesis. Algae are very similar to plants. They have chlorophyll and produce food using oxygen and the energy from the Sun. However, they are not considered plants because they do have specialized organs or tissues.