Prokaryotic diversity & phylogeny Flashcards
endosymbiont theory
mitochondria and plastids (chloroplast and related organelles) were formerly small prokaryotes that began living within larger cells
serial endosymbiosis
mitochondria evolved before plastids
infolding of plasma membrane> cell with nucleus and endomembrane system (nucleus, nuclear envelope, & endoplasmic reticulum)
what is the importance of horizontal gene transfer in the evolution of prokaryotes & early eukaryotes?
over 100 MYA prokaryotes acquired genes from even distantly related species and they continue to do so today. This is why the phylogenic tree is a hypothesis because it is always changing/evolving.
Transformation
genotype and possibly phenotype of a prokaryotic cell are altered by the uptake of foreign DNA from its surroundings.
Transduction
phages carry prokaryotic gene from one host cell to another.
chemoheterotrophic decomposers
break down dead organisms as well as waste products and thereby unlocking supplies of C, N, and other elements. Live with cease without!
Cyanobacteria
uses CO2 to produce organic compounds; also produces atmospheric O2
autotrophs
1st single-celled organisms
created photosynthesis as well as oldest fossils: stromalites (green: chl a)
Nitrogen fixers
produce atmospheric N2 which produce building blocks of proteins & nucleic acids
Domain Archaea
lack peptidoglycan divided into: halophiles, thermophiles, and menthanogens possess methionine (same as EUK) Histones associated with DNA (same as EUK) Circular chromosomes (same as Bac)
gram stain
used to categorize bacteria based on cell wall compositon
gram positive
more peptidoglycan
purple
non-disease causing
gram negative
less peptidoglycan
red
toxic and resistant to antibiotics
Conjugation
DNA transferred between two cells that are temporarily joined
Antibiotics prevent growth of peptidoglycan?
true
What is mutualism?
+/+
ex: E. Coli
What is parasitism?
+/-
ex: Trypanosoma
What is commensualism?
+/0
ex: Staphylococcus
Bacteria
peptidoglycan cell walls
one kind of RNA polymerase
absent of histones
Groups: Proteobacteria, Chlymadias, Spirochetes, Cyanobacteria, & gram positive
Enteric Bacteria
fr Proteobacteria
Ex: salmonella & E.Coli
ex: Salmonella
endotoxins
gram negative
produce food poisoning
ex: E.Coli
mutualistic symbiont
vitamin k produces blood clotting
Nitrogen fixing bacteria
fr Protebacteria
mutualistic symbionts of lugumes
Nitrogen for carbohydrates
Myxobacteria
soil dries or food is scarces, releases resistant “mycospores”
Bdellovibrios
attacks other bacteria outer covering
Chlymadias
intercellular
steals hosts ATP
gram negative
non peptidoglycan
Spirochetes
cork-like screw
internalized flagella under cell wall
heterotrophs
Gram positive
divided: actinomycetes, endospore forming bacteria, & mycoplasmas
Actinomycetes
free living decomposers ray-like form colonies of branched chains of cells non parasitic/mutualist greater majority inhabits soil antibiotics
Endospore forming bacteria
exotoxins
obligate anaerobes
deadly pathogens
resistant cells developed by certain bacteria
Mycoplasmas
lack cell walls
tiniest known cells
free living soil bacteria
Exotoxins
proteins secreted by certain bacteria and other organisms.
Endotoxins
lipopolysaccharide components of the outer membrane of gram-negative bacteria. In contrast to exotoxins, endotoxins are released only when the bacteria die and their cell walls break down.
