Protist << PROH tihst >> is the name of a wide variety of simple organisms, most of which are microscopic. This group includes protozoans, which consist of a single cell, and true algae, which may consist of one cell or many cells. Protists are traditionally classified as Protista, a biological kingdom. Many scientists no longer consider Protista a true kingdom because not all protists are closely related.
Like animals and plants, protists are eukaryotes. The cells of eukaryotes possess nuclei. Single-celled organisms that lack nuclei are prokaryotes. Bacteria and archaea are prokaryotes.
Algae and some protozoans contain chlorophyll, the green substance also found in plants. In a process called photosynthesis, chlorophyll enables these protists to use energy from sunlight to make food. Most protozoans do not have chlorophyll and must obtain energy by feeding on other protists and prokaryotes. Most protists reproduce by mitosis, a process by which one cell divides into two separate cells. Some reproduce sexually.
