Topic 9
the group of prokaryotes are
considered paraphyletic since they are bacteria and archea
describe a prokaryote
very small (0.5-5um), has a plasma membrane that protects it from its environment,has cytoplasm with cytosol in it, they have no nucleus only a circular chromosome in the nucleiod
a prokaryote has
no organelles, a capsule that's a surrounding layer or protein/polysaccharide surrounding the cell wall that protects the cell and lets bacteria stick to it
prokaryotes have fimbriae and what do they do
short hair like thingys that help bacteria stick to subtract or other cells
prokaryotes have bacteria that
donth ave histones, which are condenced proteins that bind to DNA
prokaryotes also have
a protective cell wall made of peptidoglycan (polymer)
prokaryotes aso have flagellums that
are like tails that help wil locomotion and have taxis that respond to stimulis to direct its movements
what is glam classification
bacteria is classed based on the structure of their cell wall. gram (+) or gram (-)
how is a gram (-) classified
have two layers of plasma membrane with a cell wall in between, which means they have more resistance to antibiotics and block more water
hwo are gram (+) classified
only have one plasma membrane with a cell wall, not as resistant
example of gram (-) bacteria
e coli
example of gram (+) bacteria
infections and food intoxications
are bacteria good or bad?
neither good nor bad essential to life
why are bacterial good
can aid in human health, can support ecosystems (produce produce O2 through photosynthesis), medical apllications, they decompose organic matter
why are bacteria bad
produce diseases, antibiotic resistance (led to bacteria with more resistance), food spoilage.
what does microbiome mean
group of microorganisms that live out and inside the human body
what does commensalism
a stable relationship between organisms where only 1 of the two benefits from it. doesn't harm or help
if an organisms source of energy is light is it
phototroph
if an organisms engery source are chemical compouds like glucose, H2S and NH3 is it
chemotroph
when an organism is phototroph and its crabon source is from inorganic componds like CO2 and HCO3 it is
photoautotroph
when are organism is phototoph and its carbon source is organic compounds like glucose it is
photoheterotroph
if an organis is chemotroph and its source of energy are inorganic compounds like CO2, HCO it is
chemoautotroph
if an organism is chemotroph and its source carbon comes from organic compounds like glucose and lipids it is
chemoheterotroph
what are the roles of prokaryotes in the ecosystem specifically food webs
rely on them as primary producers (point of entry for C and energy), absorbing enery and assimilating minerals
hwo do prokaryotes absorb energy for the ecosystem
absorbs energy from outside of the ecosystem (like sunlight), converts CO2 into sugars and produces O2 and proteins
how do they assimilate minerals
takes mineral from their environement to turn them into stuff they need for their body. like decomposer who break down dead stuff and trun it into nutrients. they recycle C,H,O,N,P so it moves around all things , kepping ecosystem healthy
prokryates can reproduce asexually through
binary fission (doubling in size and simple division in half. NOT mitosis
binary fission needs the replication of what
the origin replication, where the two daughter cells are clones of the mother
in binary fission the populatin what
doubles every generation
what are the phases of binary fission in order from 1st to last
lag phase, log phase, stationary phase, stationary phase and death phase
what is the lag phase
prep phase, prep all they need for growth, like proteins and enzymes, to start dividing
what is the log phase
the cells grow rapidly and start to spilt in two
what is the stationary phase
the cells stop growing and because they dont have anymore nutrients and oxygen or there's too much waste. this makes it harder for them to divide
whats the death phase
when cells run out of nutriments and oxygen and too much waste builds up so they cant survive. they stat dying and the populaiton decreases
if an organism is single celled, has a circular chromosome and has no nucleus or membrane than its a
prokaryote cell
whats the long-term evolutionary expermiment (LTEE)
lenski took 12 identical populations of e coli and put them in a low sugar environemnt t owatch them grow, divide and creat new genrations
whats the goal of LTEE
watch how the bacteria adapt to their environement over generations and understand how it works
what were the key observations in LTEE
showed change that helped them survive better. mutation to use glucose more efficiently
what was the big discovery of LTEE
the e coli adapted to use citrate as food even though theyd never done that before
what is an antibiotic
a molecule that kills or stops the growth of a bacteria
some bacteria can develop mutations that
make them resistant to an anitbiotic
what is vertical inheritance
when a bacteria survives an antibioc due to resistance it can pass this resistance to its offspring
selection will favour
resistance to antibiotics
resistance can be a problem for
keeping antibiotics, therefore needing to keep up
what is conjugation
when bacteria from the same species donates its DNA
how does conjugation work
two cells are join by a pilus (hair thingy), then establich contact (mating bridge), and then a plasmid (small circular chromosome) can be transfered
what is an F factor
fertility factor, has genes that makes the pilus
what is selfish DNA
only cares ( enhances) about its own trasnmission
what are R plasmids
resistance plasmids that has the antibiotic gene and sex geene for pilus
r plasmid can also use
congujation
R plasmid can carry gene for
antibiotic resistance
congujation is a type of
horozontale gene transfer
whats the difference between horizontale gene transfer and vertical gene transfer
horizontal is passed form organism, and vertical and passed down from parent to offspring
exmaples of horizontal gene transfer
conjugation, transduction, transformation
what is transformation
bacteria take DNA from their surroundings to add to their own
transduction defintion
bacteria exchnages DNA through a virus