Lecture 17 Protozoa Flashcards
List the defining chracteristics of Phylum Ciliophora.
1) Simple cilia or compound ciliary organelles in at least one stage of life
2) Two types of nuclei
3) Contractile vacuole present
4) Binary fission transverse
5) Sexuality involving conjugation
6) Most species free living, but many commensal,
7) Some parasitic
Ciliophora are VERY VERY abundant and DIVERSE. They have at least one cilia in a stage of their life.
Cilia allows them to move around a bit. Also allows them to move things around. If there are nutrients particles in the proximity, they can use the cilia to move them around and help in grazing.
What are the three amoebae included in Subphylum Sarcodina?
- Endamoeba blattae
- Common in intestines of insects
- Entamoeba histolytica
- Amoebic dysentery
- Naegleria and Acanthamoeba
Why should we care? They can be pretty important to human beings. They can cause amoebic dysentery.
They are very very common here in Florida. Top right image is a picture of an eye. The eye is black because of amoeba.
Naegleria and Acanthamoeba usually live in the lake. What happens to little Timmy who likes to open his eyes while swimming in the lake? These amoeba will colonize your eye, but won’t quite like living there. SO they will follow the tunnel towards the light (up your optic nerve or nose nerve) to the land of Oz (your brain). They will colonize your brain and no one else can do something about.
Define the two types of Protozoan nutrition.
-
Holozoic nutrition
- Nutrients acquired by phagocytosis
- Cytostome - used by some ciliated for phagocytosis.
-
Saprozoic nutrition
- Nutrients acquired by pinocytosis, diffusion, or carrier-
The morphology of protozoa are very similar to eukaryotes, however there is a key difference. What is it?
Protozoa have to differentiate organelles because their bodies are segregated.
What are the main differences between protozoa and prokaryotes in regards to reproduction?
Major difference from prokaryotes is that they are now able to undergo sexual reproduction - usually by conjugation.
Protozoa have sexes, but no distinguishable gentialia. Instead, there are (+) and (-) strains. One accepts genetic information and one donates genetic information.
How does Phylum Microspora cause disease in insect?
(Protozoa)
Nosema bombycis causes pebrine disease in silkworms.
1) Typical spore with one coiled filament.
2) When ingested, it extrudes the filament.
3) The parasite enters an epithelial cell in the intestine of the silkworm.
4) The parasite divides many times to form small amoebae that eventually fill the host cell and kill it.
5) , 6), and 7) Some of the amoebae with 4 nuclei become spores. Silkworms are infected by eating leaves contaminated by the feces of infected worms.
In protozoas, what is encystation?
- Formation of a cyst
- Resting state with a wall and low metabolic activity.
- Function of cysts
- Protection from changes in environment
- Sites for nuclear reorganization and cell division.
Name a few species from Phylum Sarcomastigophora and its unique characteristics.
1) Giardia lamblia. Causes Giardiasis: Gastrointestinal disorder. Giardia stays in your body for decades.
2) Trichomonas vaginalis. Causes Trichomoniasis - a sexually transmitted disease.
3) Trypanosomes. They are hemoflagellates. Important blood pathogens (e.g. causes African sleeping sickness). Probably the most studied protozoa on the planet is also one of the most deadly. What are hemoflagellates? They are guys that like to live in your blood. Much bigger than a red blood cell. The problem is that once your start collecting these organisms in your blood, it would be hard to get rid of them. Drugs would kill them, but their corpses will still stick around. Blood travels up to the brain, and their corpses can clog the fine pores in the blood/brain barrier, causing you to stroke out and die.
How to get rid of them? You would usually need to undergo some kind of blood transfusion.
Define paraphyletic.
Two groups without a common ancestor but they have been shunt together because they look similar.
List the characteristics of Subphylum Sarcodina.
- Locomotion primarily by pseudopodia
- Shells (tests) often present
- Flagella restricted to reproductive stages when present
- Asexual reproduction by binary fission
- Mostly free living
What is binary fission in protozoa?
A sexual reproduction. It is mitosis followed by cytokinesis.
List the defining characteristics of Phylum Myxozoa.
1) Spores of multicellular origin
2) One or more polar capsules
3) All parasitic, especially in fish
Have spores of multicellular origin. These guys have multicellular spores and are parasitic as well. These guys will just hang out in the fish gills all day long.
Where are most protozoa found?
- Primarily in moist habitats
- Most are free-living in aquative environments
- Terrestrial protozoa usually found in decaying organic matter and soil.
- Some are parasitic in plants and animals
What are the characteristics of a Protozoa?
- Unicellular, usually motile
- They lack a cell wall (usually)
- Chemoorganoheterotrophs
- They are NEVER multicellular!!!!!
What are hydrogenosomes?
- Observed in some anaerobic protozoa
- Small, membrane-delimited organelles that contain a unique electron transfer system
- Uses protons as terminal electron acceptors.
