Notes - Microbiology Protista Part 1 Animal like Protists - Kingdom Protista is a very diverse group of organisms. There are over 115 000 different kinds, with traits that fit with fungi, plants, and animals. - All protists are eukaryotic cells that can be either single or. It s hypothesized that the first protist was derived from many prokaryotic cells that came together symbiotically. Over time these cells became so dependent on each other that they could no longer survive on their own. This hypothesis is called the. Evidence to support this idea is found in Cyanophora paradoxa. This protist has blue green bacteria living inside of it, and can be removed to survive on its own! 1
- There are four categories for animal like protists. 1.) : cilia bearing protists can be either solitary or colonial. All ciliphora contain small hair like projections called cilia that beat back and forth to produce movement. There are over different ciliaphora and few are parasitic or symbionts. Ex. Paramecium caudatum - - Paramecium reproduces using both binary fission (primary) and (secondary). Binary fission occurs the same as in bacteria except the paramecium splits at the gullet to form a clone. occurs when the paramecium is stressed (high temperature or starvation). Two paramecium attach,, and their diploid ( ) micronuclei undergo meiosis to have 4 haploid micronuclei (N). Three of haploid micronuclei are reabsorbed by the paramecium leaving only one micronuclei, which divides into two. Each paramecium exchanges one with each other. The old fuses with the new to become a diploid micronuclei again and the macronuclei reforms. 2
2.) : flagella bearing protists (zooflagellates) may have one or more flagellum to use for locomotion. Food is absorbed through the cell membrane. May be symbiotic, parasitic, or free moving. Zoomastigina may reproduce via binary fission or asexually. Sexual reproduction occurs by forming gametes, which fuse together and form an new individual. Ex. 3
3.) Sporozoa: spore producing protists non-motile and parasitic. Infect many chordates. They reproduce by making spores. are groups of cells enclosed in a protective membrane. The spores attach to the hosts cells, penetrate, and live within the cell. Ex. Plasmodium causes malaria. 4.) : false feet protists use cytoplasmic projections for movement and food capture. The projections are called. Amoeba move by pumping cytoplasm into a pseudopod and the rest of the cell follows. - Amoeba reproduce through binary fission. 4
- Other groups in Sarcodina are the heliozoans, radiolarians, and foraminifers. Many of these groups produce shells of SiO 2 and CaCO 3. Impact of Animallike Protists - As stated earlier, some protists are parasitic. Trypanosoma (zoomastigina) live in the blood of vertebrates, and cause diseases like African sleeping sickness. This disease is spread by the tsetse fly. The protist destroys the red blood cells and other tissue. Animals become weak, fall asleep and often die. - Some protists are beneficial. Many types of protista live in the digestive tract and aid in nutrient absorption. Ex. Trichonympha (zoomastigina) that lives in termites and digests the wood (cellulose) they eat. Part 2 Plant like Protists - There are five categories for plant like protists. 1.) Euglenophyta: closely resemble the zoomastiginans in general body shape and they are flagellated. Main difference is chloroplasts that contain in the Euglenophytes. Ex. Euglena 5
- Euglena move by using their larger (of 2) flagellum like a whip or by in low water conditions, called movement. There is a red light sensing spot (eye spot) used for directing the euglena towards the most light for photosynthesising. Euglena can also gain nutrients and energy through absorption from water. Euglena are both a phototrophic autotroph or a heterotrophy in poor lighting conditions. They reproduce by when they enlarge and split from the flagellated end on down. 2.) Pyrrophyta: this phylum are also known as. Most are photosynthetic (a few are heterotrophic). They usually have ; one is wrapped around like a belt, and the other trails behind for locomotion. This phylum is covered in thick plates and is luminescent! These are the organisms that cause when you stir ocean water. There DNA is not wrapped around histone proteins and is the only eukaryotic cell that isn t! 6
3.) : golden protists only 3 kinds in this phylum: yellow-green algae, golden-brown algae, and diatoms. Very diverse group. Reproduce sexually and asexually. Diatoms produce shells largely made of. 4.) Acrasiomycota: very hard to place in any kingdom. They are now considered protists. Parts of their life cycle are like. When nutrients are exhausted they gather together and form a fungi like organism. They produce fruiting bodies and spores just like Fungi. 5.) : acellular slime molds Have the same life cycle until nutrients become scarce. Then they come together and form plasmodia. Plasmodia are a single cell with thousands of in the one cell. They then also produce fruiting bodies that make spores. 7
Impact of Plantlike Protists - Harmful - often in areas of sewage dumping. The absorb and feed of the nutrients in sewage. This causes a in the number and when they die off the bacteria that decompose them use up all the oxygen in the water. Breathing animals suffocate and die. Ex. Large blooms of Gonyaulax polyhedron cause red tides. This is a red colour in the water from the protists and the toxin they produce. The build up in filter feeders like clams and can be fatal if the clams are eaten. - Helpful plantlike protists often form symbiotic relationships. Ex. dinoflagellates with coral. The dinoflagellates allow the coral to use the energy made from and in return the dinoflagellates feed of the coral wastes. Also, % of all photosynthesis (and thus oxygen) occurs from plantlike protists. They are also a huge resource of food for larger organisms in the oceans. 8