Microeukaryotes Flashcards
Cytoskeleton
Microtubules
Microfilaments
Cortical actin skeleton
Characteristics - 7
Endomembrane system Cytoskeleton Nucleus Mitochondria Multiple linear chromosomes Sexual reproduction (haploid and diploid generations) Flagella
Microfilaments
twisted cables of actin
Microtubules
hollow rods of tubulin
Arise from microtubule organising centres or basal bodies of flagella
Cortical actin skeleton
Underlies cell membrane
Allows change of shape: phagocytosis, pseudopodia
Stress fibres protect cell from environmental stresses
Size
Mostly 5-20 micrometers
Amoeba more than a few cm
Pico-eukaryotes: 1 micrometer
Similarities
Actin -> MreB (cell elongation)
-> ParA (plasmid and chromosome segregation)
Tubulin -> FtsZ (z-ring)
Glycolysis, TCA cycle -> bacteria
Ribosomes, RNA polymerases (info transfer)-> archaea
TCA
Citric acid cycle
Krebs cycle
Mitochondria - 6
Cristae, matrix Bacteria-sized Circular chromosomes Bacterial (70S) ribosomes Mitochondrial DNA similar to rickettsias
Rickettsias -6
Parasitic bacteria Typhus, chlamydia Reproduce only inside host Energy parasites Outer membrane of mitochondrium would be hosts vacuole, inner would be rickettsias outer membrane)
Micro eukaryotes naming
Protists - all
Protozoa - only non-photosynthetic
You are what you eat scenario
An archaeon evolved to eat bacteria which later became mitochondria
(Where did the cytoskeleton come from)
Old classification -4
Amoebas
Flagellates
Ciliates
Sporozoans
Amoebas
Lobose
Radiolarians
Foraminiferans
Lobose amoebas - 4
Lobopodia, driven by actin polymerisation
Predatory, engulf and digest prey in vacuoles
Aggregate into grex or syncitium
Produce fungus-like fruiting bodies
Grex
Multicellular lobose amoebas
Slug-like organism
Syncitium
Acellular lobose amoebas
Multinuclear mass of cytoplasm
Radiolarians
Silica shells
Long thin pseudopodia = actinopodia supported by microtubules
Foraminiferans
Calcium carbonate shells
Long thin reticulopodia which fuse together in a net to catch prey
Flagellates -6
Green algae Dinoflagellates Heterokonts Euglenia Kinetoplastids Diplomonads, trichomonads
Dinoflagellates
Flagella in grooves of a shell, one forward, one helical and wrapped around cell waist
Toxic red tides
Paralytic shellfish poisoning
Heterokonts
One flagella hairy, forward pointing, thrust generating
Another plain, trailing backwards, used for steering
Brown algae, diatoms, oomycetes (water moulds)
Kinetoplastids
Parasites (sleeping sickness, chaga’s disease)
One long flagellum attached to undulating membrane
One giant mitochondrion at the base of flagella (kinetoplasts)
Diplomonads
No mitochondrium Giardia Looks like 2 cells joined together 2 nuclei 8 flagella Attach to host intestines
Trichomonads
No mitochondrium
Instead have hydrogenosomes that produce H2
Bundle of flagella
Ciliates
Cilia beat in unison driven by network of microtubules
Most complex unicellular organisms
Permanent mouth (cytostome) and gut (cytopharynx)
Predatory
2 nuclei
Macronuclei for gene expression
Micro nuclei for reproduction
Apicomplexans
= sporozoans
Apical complex = organelle used to penetrate host cells
Multi-host parasites
Malaria (plasmodium), toxoplasmosis
Closest relative of animals
Choanoflagellates (collar animalcules)
Resemble feeding cells of sponges
Inter-domain similarities -5
Streptomycetes = fungi Slime moulds = myxobacteria Yeasts = g+ cocci Flagellates = rod-shaped bacteria Cyanobacteria = algae
