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describe prokaryotes :
first organisms on earth 3.5-3.8 BYA
ubiquitous
live on and in every other living organisms
most harmless and essential to all life
anoxic
no molecular oxygen
what organisms lived in the ancient atmosphere?
anerobic organisms
phototrophs
autotrophic organisms that convert solar energy into chemical energy
cyanobacteria
blue-green algae that evolved from simple phototrophs
what began oxygenation of the atmosphere?
ancestral cyanobacteria
what allowed the evolution of other life forms in the ancient atmosphere?
increase in O2 concentrations
what is the most abundant photosynthetic organism on Earth?
marine cyanobacteria, Prochlrococcus
extremophiles
adapted to grow under extreme conditions
deep see vent, heat, dry, cold, radiation
what are deinococcus radiodurans ?
prokaryotes that tolerate very high doses of ionizing radiation and heat
dead sea
hypersaline basin that is 10x saltier with 40x more magnesium than sea water
halophiles
prokaryotes that live in the dead sea that have divalent cations, are acidic, and have intense solar radiation
who discovered the techniques for pure culture including staining and growth media?
Robert Koch
culture medium
contains all the nutrients needed by the target microorganism and can be liquid(broth) or solid (agar)
what should there be after an incubation time at right temp in a culture medium?
evidence of microbial growth
pure culture
lab culture containing a single species of microorganism
what should agar of a person with strep look and why?
the agar should be clear bc strep lyses the red blood cells
colony
a visible mass of microorganisms originating from a single mother cell
incubation
maintaining controlled environmental conditions for the growth of bacteria
are prokaryotic or eukaryotic cells smaller?
prokaryotic cells
predominantly single-celled organisms of the domains bacteria and archaea are classified as…
prokaryotes
what 4 common structures do all cells have?
plasma membrane
cytoplasm
ds DNA genome
ribosomes
plasma membrane function
fxns as a barrier for the cell and separates cell from environment
cytoplasm
complex sol’n of organic molecules and salts inside cell
ds DNA genome
informational archive of the cell
ribosomes
sites of protein synthesis
pro and karyon mean?
before and nucleus
eu and karyon mean?
true and nucleus
what are the 3 main categories of shapes for prokaryotes?
cocci
bacilli
spirilli
cocci
spherical/round
bacilli
rod-shaped
spirilli
spiral-shaped
what can prokaryotes occur in when speaking of terms of shape?
pairs
chains
tetrads
clusters
what do prokaryotes not have in their structure?
membrane-bound organelles
nucleus (DNA in nucleoid)
microtubules
microtubules
mechanical support for cell division and movement
nuceloid region
region that contains DNA
plasmids
extra chromosomal DNA
pili
help w/attatchment
flagellum
help w/movement
what do the capsule, cell membrane, and cell wall do/ where are they?
capsule -outer
cell membrane-innermost
cell wall- middle and give structural support to protect from lysis
what features aren’t found in all prokaryotes?
flagella, capsules, and pili
is archaea closer related to eukarya or bacteria?
eukarya
what are the gram negative bacteria?
proteobacteria
chlamydias
spirochetes
cyanobacteria
what are eukaryotic mitochondria thought to be derived from?
proteobacteria
proteobacteria
includes N-fixing bacteria and common gastrointestinal pathogens like food poisoning
what are examples of proteobacteria?
escherichia coli
salmonella(food poisoning)
vibrio cholerae (diarrheal illness)
chlamydia
all are endoparasites (live w/in animal cells)
what does chlamydia cause?
eye infection or pneumonia in children of infected women
pelvic inflammatory disease, leads to infertility
what is chlamydia preventable or curable by?
antibiotics
spirochetes
spiral shape and free-living that include disease-causing pathogens
what an example of a spirochete ?
syphilis (STD)
what is the causative agent of syphilis?
traponema pallidum
what is another example of a spirochete?
lyme disease which is fever and skin rash
what bacteria causes lyme disease?
Borrelia burgdorferi
vector
carry a disease from an infected animal to another who is uninfected
cyanobacteria
plant-like, O2 generating photosynthesis and some are N-fixers
N-fixers
convert nitrogen gas N2 to ammonia NH3
heterocyst
specialized nitrogen fixing cells that fix nitrogen that is used for growth of cyanobacteria
what does cyanobacteria do to make toxins ?
blooms
gram-positive bacteria
include decomposers in soils and pathogens
what an example of gram-positive bacteria?
Bacillus anthracis
decomposers
break down dead organic material in the soil into CO2, H2O, nitrogen, phosphorus
what do tetanus shots protect us from?
Clostridium tetani
what is MRSA resistant to?
meticicllin which is spread by skin to skin contact
what causes skin infection?
staphylococcus areus
what does streptococcus cause?
strep throat and scarlet fever
what does the domain archaea include ?
extremophiles and methanogens, but they may live in normal conditions
are there any human disease causing archaeans ?
no
methanogens produce what?
methane CH4 as a by product of anaerobic respiration
what does the prokaryotic plasma membrane do?
controls what goes in and out of the cell
selectively permeable
keeps ions, proteins, and other molecules w/in cell preventing diffusion into extra cellular environment
what’s the structure of the plasma membrane ?
phospholipid bliayer composed of 2 layers of lipid molecules
bacterial membrane
fatty acids linked to glycerol
arcaheal membrane
branched isoprene chains linked to glycerol
what are the 2 differences between a phospholipid from archaea vs one from bacteria and eukarya?
archaea have an ether linkage while bacteria and eukarya have an ester linkage
archeas is joined tg bacteria and eukarya is not
what does gram strain reflect ?
cell wall type
gram +(pos.) bacteria
bacteria w/thick peptidoglycan layer
what does gram + bacteria stain?
purple
gram stain
based on differences in cell wall and structure of bacteria
who invented gram stain and when did they?
Hans Christian Gram in 1882
what percent of the wall is peptidoglycan and what is the leftover made of in gram + bacteria ?
90 and the leftover is Teichoic acid
gram -(neg.) bacteria
bacteria w/thinner peptidoglycan plus an outer lipopolysaccharide bilayer membrane
what are characteristics of the lipopolysaccharide layer?
it is toxic, resists drugs, and immune system
what does gram + bacteria stain?
pink
how much of the cell wall is peptidoglycan in gram - bacteria?
10%
what is a gram - bacteria?
safranin which is pink
what is a characteristic describe the prokaryote structure?
many have a capsule or slime layer
do prokaryotes secrete sticky carbs & proteins out cell wall ?
yes
what do prokaryotes glue tg or glue to?
they glue tg cells or to the surface
what do prokaryotes resist ?
attack from immune system
what do prokaryotes hold in?
moisture
what is significant abt nostoc filaments?
they are held tg by slime and make a easily visible mass
what are all hairlike structures of prokaryotes and what do they do?
flagellum (multiple flagella) that act as an organelle for motility and extension
fimbriae
hair-like protein that are short pilli which help cells stick to surfaces and each other
what can prokaryotes form?
a sex pillus which is a mating bridge for a type of HGT
pili
pull 2 bacteria cells tg for DNA transfer (conjugation)
