Protists All

Unicellular group of eukaryotes (some are colonial or multicellular). More complex then porkaryotes. Predecessors of plants, fungi, and animals. A single protistan cell must perform all the basic functions performed by the collective of specialized cells in plants and animals

Most protists are aerobic, possessing mitochondria and using aerobic respiration.

1) The Protozoa - the heterotrophic, animal-like protists (ciliates, flagellates, etc.) 2) The absorptive, fungus-like protists (water molds and slime molds) 3) The Algae - the photosynthetic, plant-like protists (red algae, green algae, etc.).

Excavata, Chromalveolata, Rhizaria, Archeaplastida, and Unikonta.

Members of this clade have a ‘excavated groove’ on the side of the body. Some have a flagella that differ from other organisms. They include parasites, predatory, photosynthetic species. Controversial Supergroup.

The diplomonads, the parabasalids, and the euglenozoans

Lacks plastids and has a modified mitochondria (mitosome). Mostly found in anaerobic environments. 2 equal sized nuclei and multiple flagella. Mostly parasites (including Giardia intestinalis- inhabits mammals intestines).

Lack plastids and have a modified mitochondria (hydrogenosomes- creates energy anaerobically and releases hydrogen gas as byproduct). Most common is Trichomonas vaginalis, a sexually transmitted parasite in humans.

Flagellates with anterior flagella (rod with spiral or crystalline structure inside flagella. They reproduce by binary fission. Some euglenoids are photosynthetic. One group (the kinetoplastids) includes the parasitic flagellates that cause sleeping sickness (Trypanosoma). The kinetoplastids like Trypanosoma have a single large mitochondrion with a mass of DNA (the kinetoplast

Has a pocket at one end of the cell where1-2 flagella emerge. Most are mixotrophs (In sunlight they are autotrophic. When light is absent they become heterotrophic, absorbing organic nutrients from their environments. Also they engulf prey by phagocytosis.

DNA sequence suggest this group is monophyletic group. Evidence suggests that common ancestor engulfed a single-celled red alga (a billion years ago) and through endosymbiosis, formed a new type of cell. Two groups of chromalveolates: the alveolata and the stramenopila.

The alveolates have subsurface cavities called alveoli. These diverse group includes: Dinoflagellates (group of flagellates), Apicomplexans (parasites), and Ciliates (cilia).

Dinoflagellates (responsible for red tides). Found in marine and freshwater systems as plankton. Their flagella and outer plates of cellulose give them both their shape and behavior. The algal blooms are reddish because of the accessory pigments (xanthophylls). Toxins in these organisms kill fish and other organisms, and can kill humans as well.

Apicomplexans are parasites of many animals. They cause diseases like malaria. The apicomplexans have a organelle or structure called the apical complex that aids in invading host cells. The genus that causes malaria in humans, Plasmodium, typically has two hosts: an intermediate host in which asexual reproduction takes place (Humans) and other place where sexual reproduction occurs (mosquito).

The ciliates are a large group with the outer surface usually covered with rows of cilia used to move and feed. A ciliate has a large macronuclei (involved in day-to- day activity of the cell- feeding waste removal etc., consists of many copies of the genome) and one or more micronuclei (involved in sexual reproduction). Ciliates use a form of sex called conjugation.