3 Cells 2 Flashcards
cyanobacterium
photosynth.. blue/green algae produces O2: -oceans from blue to green -precipitation of aqueous iron -killed most life on earth: great oxygenation event 2.3 bill yrs ago
primordial earth
anerobic and very acidic
there are still some niches like that
layered rocks in Austrilia
layers of RUST
due to changing oxygen levels
begining of movement to life on land started with the atmosphere started getting oxygen
Layered rocks theory 1
O2 production caused ecological catastrophe, ecosystem collapsed and it took a long time for it to recover and for cyannobacteria to produce enough oxygen again
it was a SLOW event
Layered Rock Theory 2
Global Ice Ball Theory
O2 oxidizes of methane
lots of bacteria produce methane as a byproduct
there was lots of methane in atmosphere before cyannobacteria (so earth was very warm)
cyannobacteria introduces oxygen: planet freezes over
thaw again, oxidation, methane causes warming, etc
lots of freezing and thawing
pores and transport systems
active/passive
secretion systems
send complexs/proteins beyond the membrane
- pili:transmission of DNA
- flagella: motillity
- toxin secretion: assembly of things outside of the cell
goal of cells:
use nrg to do work outside of cell
ATP… you can’t send it outside of the membrane
isntead charge and transport things out to do work
Active vs. passive transport
whether based on conc gradient or ATP use
passive transport
movement of small molecs
based on conc gradient
aquaporin
water only
passive, based on gradeint
nonspecific transporters
anything goes back and forth
passive, based on gradeint
specific transporters
use no nrg, but use only specific things
passive, based on gradeint
facillitated diffusion
uses channels and carrier proteins
specific, passive, CAN BE SATURATED
osmosis
water transport
based on salt concs on either side of cell
isotonic, hypotonic, hypertonic
remember, water can move across membrane, not salt
isotonic
concs of salt and water on same on inside and outside of cell
net 0 diffusion
there is movement of water molecs, but not NET change
very good for cell
hypertonic
more water inside cell, more salt outside
water moves out
cell shrinks, not lethal though
hypotonic
more salt inside cell
swelling and lysing for cells with weak walls because water rushes in
how to avoid lysing of bacteria in hypotonic solution?
cell wall!!!
peptidoglycan layer is a lattice that prevents bursting
resistant to hypo and hyper
how do BODY CELLS deal with gram positive bacteria
surround it with a ton of water (create hypotonic solution around the bacteria cell)
break cell wall with enzymes
lysing bc no more cell wall
how we use hypertonic solutions
pickle juice
salting meat
does not sterilize!!!!! bacteria dont spoil the food because we slow them down, but theyre not dead
active transport
use energy to transport sugars, amino acids, organic acids, inorganic ions
ususally involves binding of things like ATP and the target to the transport protein, hydrolysis of ATP, conf. changes
bacterial secretion
of a sticky sugar called glycocalyx
glycocalyx
defense: avoid dehydration (survie dessication: immediate deydradtion)
slime layer on bacterial surface. stifky
made inside of cell and secreted out
slime layer of capsule
function of glycocalyx
attachment to surfaces… aid in colonization
protect from desiccation/dehydration
nutrient trap
virulance factor: protects from phagocyotisis from immune cell
- if immunse cell grabs it, it can’t hold on
capsule vs. slime layer
capsule is more organized and better attached
S layer
on surface of gram positive bacteria
inert, sit. protection and adhesion
purifying them makes them self assmble into strucutre that perfectly fits around the bacteria.
wound spring… have a little nrg that makes them self assemble
spore
way for bacteria to survive in exterme environemnts
preserve genetic material
kind of secreted
MOSTLY GRAM POSITIVE (a few gram negative have it too)
spores are resistant to…
heat radiation toxins antibiotics dessication
net number of cells with endospore formation
is zero
mother cell dis
what do spores look like in cells?
light, nonstaining areas within cells
what kills spores???
Bleach!!!!!!!!!
formation of endospores
assymetric division
engulf the smaller cell (both contain genetic material)
mother dies: so NOT a replication event (no net gain of cells)
genome equivalent: not number of cells, number of genomes
Quarum Sensing
communication and determination of local concs of same and other species of bacteria
Autioinducer systems and quarum sensing
secrete small diffusible compounds
bacteria react to high concs of chems and alter their gene expressions
atp to make light
light organ squid
vibrio fisheri: produce visible light at high bacteria concs in
Squid have it in bellies
contract light organ to make more light
bellies so that predators cant see them when they pass over moon and create shadow
squid produces sugar so that the bacteria grows in its light organ
how do bacteria know concentration
quarum sensing
decsion making based on concs: inter and intra species
sense conc of metabolic byproducts (waste)
thus they know how many other bacteria are around
can direct them how fast to eat/metabolize
Biofilms: quarum sensing
protect from immune system, dislodging organized group of bacteria matrix of bacteria and glycocalyx. functions like multicellular organism inc anitbioitc resistance plaque on teeth
make descsions based on conc. from free living bacteria to adhesive form.
3 things protein complexes do
secretion
adhesion
motility
central dogma
DNA-> RNA-> proteins->work!
solved by Crick
S (spedbergs)
rate of sedimentation
affected by density, size, and shape
measures the particle moving through a thick solution
the two RNA subunits are more effective when the move together, thats why the number is smaller
