Unit 7 Flashcards
what do eukaryotic cells contain?
organelles
- nucleus
- mitochondria
- GA
- ER
- chloroplasts
what are eukaryotic cells bc of endosymbiosis?
genetic chimera
what are the two energy producing organelles?
mitochondria and chloroplasts
what are mitochondria ancestors of?
respiratory bacteria
what are chloroplasts ancestors of?
phototrophic bacteria
where did mitochondria and chloroplasts get their own DNA from?
bacteria
what is the endosymbiosis hypothesis?
- established residence inside another cell type
- host cell was safe and stable
- M and C gave host cell ATP
what is the support for the endosymbiotic hypothesis?
- mito and chloro have own DNA
- eukaryotic nucleus have genes from Bacteria
- organellar ribosomes and phylogeny
- antibiotic specificity
- hydrogenosomes
mitochondria and chloroplasts contain DNA
- proteins are encoded by nuclear DNA
- molecules encoded by organelles genes: respiratory chain proteins (mito), photosynthetic apparatus proteins (chloro), r RNA/ t RNA
- circular, covalently closed genome (prokaryotic feature)
eukaryotic nucleus contains genes from B
- ancestor of mito (chloro) had the genes
- engulfed cells showed up (intake of bacterial cells)
- genes transferred to host nucleus during transition
organellar ribosomes and phylogeny
- 70S ribosomes (bacterial feature)
- cytosolic ribosomes in eukaryotic cell are 80S
antibiotic specificity
- antibiotic kill or inhibit B by interrupting 70S ribosome protein synthesis functions
- same antibiotics also inhibit protein synthesis in mito anc chloro
hydrogenosomes
- membrane enclosed organelles
- own DNA and ribosomes
- in certain amitochondriate eukaryotic anaerobes
- phylogenetic analyses of hydrogenosome r RNA show connected to B phylogenetically
primary endosymbiosis
gave rise to chloroplast in common ancestor of green algae, red algae, plants
- mito
- chloro
- hydrogenosomes
- organelles from B
common ancestor + chloroplasts = ?
green algae, red algae, plants
secondary endosymbiosis
red and green algae
- cells engulfed: new cell became phototrophis
- chloroplasts stably retained
- euglenids
- chlorarachniophytes
what is the presence of chloroplasts explained through?
secondary symbiotic event in green algae
phylogenetic lineages of eukarya
- eukarya closer to A than B
- 18S r RNA (unreliable)
microbial eukaryotes contain ??
either mitochondria or hydrogenosomes or some DNA traces of these structures
what did mitochondrion or similar strucutre do?
gave new metabolic capabilities to early eukaryotic cell triggering evolutionary branching of eukaryotic microogranisms
what was the primary endosymbiotic event triggered by?
O2 accumulation after cyanobacterial photosynthesis
what are the 2 clear points in evolution of eukaryotic microbes?
- composite phylogenetic tree should be created for microbial evolution based on 18S r RNA and other genes
- primary eukaryotes acquired mitochondria- key evolutionary success of domain Eukaryotes
what are the 7 groups of microbial eukaryotes protists?
- diplomonads
- parabasalids
- euglenozoans
- alveolates
- stramenopiles
- cercozoans and radiolarians
- amoebozoa
diplomonads
- 2 nuclei of equal sizes
- mitosomes (reduced mito with ETC)
- no genes for many metabolic pathways
parabasalids
- parabasal body (structural support to GA complex)
- no mito
- hydrogenosomes present
- lack introns
trichomonas vaginalis
- parabasalids
- STD
euglenozoans
- unicellular, flagellated protists
- kinetoplastids
- euglenids
kinetoplastids
mass of DNA in single, large mitochondrion
euglenids
- 2 flagella and chloroplast
- feed on bacteria via phagocytosis (process of surrounding a particle with portion of flexible cytoplasmic membrane to engulf particle and bring it into cell for digestion)
- chloroplasts that support phototrophic growth
- in dark lose chloroplasts and live as chemoogranotrophs
alveolates
cytoplasmic sacs located under cytoplasmic membrane - alveoli
- alveoli help maintain osmotic balance by controlling water influx and efflux
types of alveolates
ciliates - paramecium
dinoflagellates - “red tides” in polluted coastal zones, blooming
apicomplexans - plasmodium species-malaria, toxoplasma, structures for sporozites for transmission of parasite to new host
types of stramenopiles
- have flagellum
diatoms
oomycetes
golden and brown algae
diatoms
unicellular, phototrophic, microbial eukaryotes
major components of planktonic microbial community in marine and fresh water
oomycetes
water molds
golden and brown algae
gold- chrysophytes
brown - not microbes
cercozoans
foraminiferans
- exclusively marine and form shell-like structures
amoebozoa
- lobe-shaped pseudopodia for movement and feeding
- gymnamoebas- free-living protists in aquatic and soil
- entamoebas- parasites for vertebrates and invertebrates
fungi
- large, diverse and widespread
- yeasts, mushrooms, molds
- 100,000
- phylogenetic cluster distinct from protists
- microbial group most closely related to animals
- in soil or dead plant matter
- role in mineralization of organic carbon
- plant pathogens
- some diseases
- establish symbiotic associations with plants - facilitate acquisition of mineral from soil
- benefit humans through fermentation and making of antibiotics
very small green algae and colonial green algae
volvox
- flagellated cells
- some motile
- photosynthesis or repro
