Protists are one-celled organisms. Symbiotic protists are protists that live with other larger organisms in a mutually beneficial relationship. The anaerobic parabasalid species of protist is an example. Photosynthetic protists are the protists that process sunlight. The dinoflagellates Noctiluca and Pyrocystis are examples of this type of protist. There are also protists that serve both purposes: they are both symbiotic and photosynthetic. The protists zooxanthellae are an example of this type of protist.