Terms Flashcards
What are the three classes of protozoa?
Trypanosomatids, Apicomplexa, and other
How were protozoans discovered and what does the word mean?
protozoa= first animal. discovered with the invention of the microscope in 1675
What are the different groups of protozoans?
Amoebae, Flagellates, Ciliates, Sporozoa, Microsporidia
How big are protozoans?
10-50 microns (um)
Where do protozoans digest their food?
in vacuoles
Do protozoans have a cell wall?
no
Why are these protists considered to be animal-like?
they move like animals and have complex metabolic activity that is similar to animal cells. They resemble animal cells more than single cell
Define niche selection
selected to live in a specific essential niche defined by anatomical, physiological, and biochemical features of the site
What factors affect pathogenesis?
niche, metabolic requirements of the parasite, and population density
By which processes does food get into and out of the protozoa?
active transport, phagocytosis, pinocyotisis (IN)
diffusion or exocytosis (OUT)
By which means do ameoboids move?
pseudopodia (actin filaments rearranging along the cell membrane)
What is the movement difference between cilia and flagella?
cilia move back and forth in a flailing motion, flagella move in a rotational manner
By what methods do protozoa reproduce asexually?
binary fission, multiple fission (aka schizogony), and budding
By what methods do protozoa reproduce sexually?
conjugation and gamete fusion
When do we most often see sexual reproduction in protozoa?
in protozoa with an insect vector stage
Define trophozoite
any stage in a protozoan’s life cycle that can digest food (the motile form usually)
Define cyst
non-motile form, protected by a membrane (infective stage)
Define excystation
process of emergence of the trophozoite from the cyst
Name some organisms in the apicomplexa?
toxoplasma (toxoplasmosis), plasmodium (malaria), cryptosporidium parvum (cryptosporidiosis)
What are some defining characteristics of Apicomplexans?
- all species are parasitic
- usually without cilia or flagella
- single type of nucleus
- have an apical complex involved in host cell penetration (gives the class its name)
- most have an apicoplast
What is the function of rhoptries, micronemes and dense granules in the apical complex?
they discharge substances into the host cell during the invasion process. They play a role in destabilizing the host cell membrane and forming an invasion pit
Why are apicoplasts considered plastids?
because drugs against chloroplasts and prokaryotes also kill apicomplexans
Describe the theory as to how apicomplexans have 4 cell membranes
eukaryotic heterotroph eats cyanobacterium (contains chloroplast), which was then engulfed by the apicomplexan ancestor
What is the function of an apicoplast?
possibly involved in lipid metabolism, is necessary for invading cells
