ch 9 Flashcards
what force drives the formation of certain shapes between fatty acids and P.lipids
hydrophobic effect
what shape do fatty acids make in water
they create circles of micelles
what shape do p.lipids make in water
they create a lipid bilayer
what are two features of p.lipid bilayers that make them good for cell membranes
1) selective permeability
2) portals like proteins and enzymes
how is the membrane structure of Archaea different from that of bacteria
they have a monolayer and branched hydrocarbons, they also have no ester bonds
how do those features that archaea have help them live in acidic hot waters
they have long saturated chains that are branched which makes it dense. they also have Ether bonds because they dont react as easily as esters when in contact with acid
which organisms lack cholesterol in their membrane, where can we see this in our own bodies
bacteria lack it and we can see this from mitochondria
why is cholesterol important
we have many vitamins and hormones that are derived from them
how does cholesterol modulate fluidity
it can insert itself in more packed fatty acids to make it less packed and rigid and vice versa for less packed, it can push the fatty acids to bring them together to make them more rigid
what are four major phospholipids in plasma membranes
1)phosphotidylethanolamine
2)phosphotidylcholine
3)phosphotidylserine
4)sphingomylin (has choline)
what are the charges of each of these lipids 1)phosphotidylethanolamine
2)phosphotidylcholine
3)phosphotidylserine
4)sphingomylin
1) 0
2) 0
3) -1
4) 0
where would you find each of these lipids
1)phosphotidylethanolamine
2)phosphotidylcholine
3)phosphotidylserine
4)sphingomylin
1) and 3) in the inner membrane and 2) and 4) in the outer membrane (choline is usually on the outer membrane)
where are the phosphocholine lipids more prevalent
outer membrane
how do these phosphocholine lipids get to the ECM
flipase
what happens if phosphatidylserine is exposed to the surface
it signals to the body that that cell is ready to die
which P lipids contribute to the negative charge on the inner leaflet of the membrane
1) phosphotidylserine 2) phosphotidylinositol 3) phosphotidylphophatic acid
what is the membrane potential
around -60 mv
what is an action potential
the depolarization and repolarization of the cell membrane potential by influx and reflux of ions
what causes an action potential
the influx and reflux of ions
what are two functions of the membrane potential of the cell membrane
- propagation of electrical impulses 2. battery, storage of energy
what are proteins that go through the cell membrane called
transmembrane
what are proteins that are hooks onto the outside of the membrane called
inosital bound proteins
what are proteins that sit outside of the membrane called
peripheral proteins
what is a translocon channel
protein that allows for the lateral movement of hydrophobic portions of a protein into the cell membrane
name one other process structure that allows the lateral movement of hydrophobic protiens
lipid rafts by cholesterol
what do lipid rafts move and how do they move them
they move GPI bound protein by increasing density relative to the raft
what are lectins
proteins that can read the sugar code on certain proteins to see if theyre foreign or not
what are integrins
proteins that help in the process of extravasation
what is simple diffusion
movement from high to low conc doesnt need any help to move through membranr
what is facilitated diffusion
passive movement of molecules along conc gradient its selective using its pores and carriers
what is active transport
movement against the conc gradient and uses energy
what are the three major facilitator of transport:
carriers, pores (transmembrane), and permeases (have various conformations)
what are aquaporins
they are protein pores/water channels that increase water transport keeping the osmotic pressure. rapid transport of water
what type of transport are aquaporins associated with
facilitative
why must transporters be used to move ions across membrane
because membrane is greasy and hydrophobic while ions are charged and hydrophilic so they dont mix
how does the structure of valinomycin antibiotic help it to transport ions across the membrane
it has the ion encapsulated by a circle with isopropyl groups on the outside that is hydrophobic and carbonyl groups on the inside which is hydrophilic
how do these ionophores kill bacteria
they disrupt the electrochemical gradient(membrane potential)
