Protists are eukaryotic, mostly single celled but some are multi-celled, microscopic organisms. There is a membrane around their nucleus. Some get their nutrients from eating other organisms, but some get it from the sun making some autotrophic and some heterotrophic. most reproduce through division of the cell. Protists produce sexually and asexually. A lot of them are parasitic and live in water. They are not bacteria because they have complex cells.