Lecture 3 - protozoans Flashcards
5 features of a protazoan
1 - single celled 2 - eukaryotic 3 - motile 4 - heterotrophic 5 - complex
what is the pellicle
cytoskeleton and cell membrane of a protozoan
some protozoans have a hardened outer structure what is this called?
test
describe the 3 methods of locomotion of a protozoan
1 - flagella - propelle forward in wave motion
2 - cilia - beat in metachronal waves - move stuff over it
3 - pseudopodia (false feet) - temp extention of the body due to changes in fluidity of cytoplasm
3 ways protozoans aquire food
1) pinocytosis - conc gradient
2) receptor mediated endocytosis - food receptors on membrane
3) phagocytosis - lysosomes release digestive enzymes
what is the though origin of protozoans?
endosymbiont theory - engulfing prokaryotes with useful characteristics -> heterotrophic eukaryote
4 main types of protozoan
1) amoeboid
2) spore-forming
3) flagellates
4) ciliates
describe amoeboids
asexual, move mainly by pseudopodia, have free living and parasitic forms
describe spore forming (apicomplexans)
complicated sexual and asexual, spread by infectious cells (sporozites) , parasitic mode of life (plasmodium - maleria)
describe the lifecycle of plasmodium (maleria)
mosquito bites transferring sporozites which divide into merozoites and gametocytes - moquito bites infected person and picks up gametocytes which are fertilised in the gut and produce sporozites which migrate to salivary glands of mosquito
describe flagellates
reproduce asexually through binary fission , move by flagella, free living symbiotic forms and parasitic forms
describe the parasitic flagellate trypanosoma brucei
transmitted by an intermediate host (tsete fly) - has 2 sub species 1) gambiense - involves humans
2) Rhodesiense - involves game
- has a variant surface glycoprotein so is difficult for host to develop immunity
what is zoonosis
when humans get involved in parasitic lifecycles
describe ciliates
asexual and sexual - move by cilia - free living and sessile forms
