Lecture 13- Protozoa Flashcards
what kingdom are Protozoa from?
Kingdom Protista
what is the main characteristic of Kingdom Protista?
made up of all single-celled organisms
how are protozoans generally defined?
protists that exhibit more “animal-like” characteristics than other groups (commonly motile and do not generally photosynthesize)
protozoans live in what parts of the body?
gut, mouth, skin, blood, liver, spleen, genital tract, lungs, brain, and the heart
what are the groups of protozoa that infect humans?
- Amoebae
- Flagellates
- Ciliates
- Sporozoa
what are the species of each of the four infectious protozoan groups?
- Amoeba: Entamoeba
- Flagellata: Trypanosoma, Leishmania, Giardia
- Sporozoa: Plasmodium, Toxoplasma, Cryptosporidium
- Ciliates: Balantidium
what are some general notes of protozoa?
- exhibit a wide variety of morphologies
- less than 50um in size
- have a complex subcellular organization
- no rigid cell walls
- all digest their food in vacuoles
- often gain host entry orally or through the bite of blood sucking vectors
- carry out complex metabolic activities
- organelles have similar functions to those of higher animals
- more like an animal than a single-cell
what is the niche selection of protozoa?
selected to live in a specific essential niche defined by anatomical, physiological and biochemical features of the site
what is protozoa pathogenesis related to?
niche, metabolic requirements of the parasite, and population density
what does the complex life cycle of protozoa involve?
- sexual and asexual reproduction
- mainly form a resistant cyst stage
how do protozoa ingest nutrients?
either via active transport, phagocytosis or pinocytosis
protozoa have traditionally been divided on the basis of their means of ____
locomotion
protozoa reproduce asexually by …
-binary fission
-multiple fission
(variations on mitotic division)
protozoa reproduce sexually by …
gamete fusion
where does gamete fusion occur?
mainly in protozoa with an insect vector stage
definition of a trophozoite:
any haploid stage in a protozoan’s life cycle which can ingest nutrients. in some parasites it is the motile form
definition of a cyst:
non-motile form, protected by a membrane. often the ‘infective stage’