prokaryotes Flashcards
what are the groups prokaryotes are divided into
bacteria and archea
how do we define bacterial species
-species concept
-not based on interbreeding or regions
-nucleotide sequence (gene/genome)
how did we used to define bacterial species
-morphological features
-shape, staining patterns, biochemical tests, growth patterns
how much of the DNA need to be the same to be considered the same species
97% 16S rRNA identity
how much of the DNA need to be the same for the species to used to have been the same
70% homology by hybridization
what is the average nucleotide identity
96%
based on staining patterns in lecture two how did we used to divide bacteria into groups
gram pos ( plus acid fasting positive) and gram negative
gram positive bacteria
-low G+C
-high G+C
-acid fast bacteria
gram neg bacteria
protoeobacteria
why is it hard to devide bacteria based off staining
-pattern is sometimes wrong
-chlamitia-no cell wall but has peptiglycan
-mycoplasm- co cell wall and no peptiglycan
-rickettsia- too small
-deep brancing bacteria-stain gram + with a top layer
what are protobacteria
-purple bacteria and their relatives
-16S rRNA gene sequencing
-gram -
-subdivided into
-alphaprotobacteria
-betaprotobacteria
-gammaprotobacteria
-deltaprotobacteria
-epsilonprotobacteria
alphaprotobacteria
-olingotroph (grow in low nutrient environment)
-can N fix
-chlamydia and rickettsiae
-obligate intracellular pathogens
chlamydia life cycle
-alphaprotobac
-over 72 hrs
-cell releases elementry bodies (active, infectious form)
-12 hrs go into and infect epithelial cell
-start turing into reticulate bodies(metabolically active)
-24 hrs inclusion
-start turning into elementary bodies
-once all elementary then they are released
betaproteobacteria
-eutrophs (grow in high nutrient environment)
-nessieria and bordetella pertussis
gammaprotobacteria
-largest and most diverse group
-aerobic or facultative aerobes (can switch to ferm if O2 isnt present)
-has different families: pseudomonaceae, pasteurellaceae, vibrionaceae, legionellaceae, enterobacteriaceae
-coliforms (ferments lactose-acid and gas production) (E. coli)
-non-coliform (do not ferment lactose or incomplete-no acid or gas)(salmonella)
deltaprotobacteria
-sulphate-reducing bacteria (SRB)
-meaning final electron acceptor in ETC
-anaerobic resperation
-bdellovibrio (vampire/predatory bacteria)
-myxobacteria (slime bacteria) (motile and highly social, multicellular “fruiting bodies, have myxospores(metabolically inactive round cells, thick walled, survive harsh conditions))
epsilonprotobacteria
-smallest group
-microaerophillic (need O2 but not too much or they die)
-campylobacter and helicobacter
how would you tell alphaprotobacteria form betaprotobacteria
based on their ability to grow in low (oligotroph) or high (eutroph) nutrient environments
non-protobacteria, gram-, spirochetes
-long, thin, spiral shaped
-difficult to gram stain
-dark field fluorescent microscope
-difficult to grow in the lab
-axial filament for motility
-borrelia (lyme) and treponema (syphalis)
non-protobacteria, gram -, cytophaga, fusobacterium, and bacteroides
-phylogenetically diverse
-rod shaped bacteria
-anarobic (strict or aerotolerent)
-fermenters
non-proteobacteria, gram -, planctomycetes
-aquatic environments
-budding cell division
-swarmer cells + sessile cells
non-proteobacteria, gram -, phototrophic bacteria
-cyanobacteria
-oxygen producing
how do sparochetes differ from bacteroides
its shape- spiral vs rods
actinobacteria
-high G+C
-gram pos
-thin filamentous barnching rods to coccobacilli
-large and complex to smallest and independently living organisms
-found in the soil,but some are aquatic
-majority are aerobic but not all
-acid fast bacteria
