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