ch 9

Question 1

what force drives the formation of certain shapes between fatty acids and P.lipids

Answer 1

hydrophobic effect

Question 2

what shape do fatty acids make in water

Answer 2

they create circles of micelles

Question 3

what shape do p.lipids make in water

Answer 3

they create a lipid bilayer

Question 4

what are two features of p.lipid bilayers that make them good for cell membranes

Answer 4

1) selective permeability
2) portals like proteins and enzymes

Question 5

how is the membrane structure of Archaea different from that of bacteria

Answer 5

they have a monolayer and branched hydrocarbons, they also have no ester bonds

Question 6

how do those features that archaea have help them live in acidic hot waters

Answer 6

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

Question 7

which organisms lack cholesterol in their membrane, where can we see this in our own bodies

Answer 7

bacteria lack it and we can see this from mitochondria

Question 8

why is cholesterol important

Answer 8

we have many vitamins and hormones that are derived from them

Question 9

how does cholesterol modulate fluidity

Answer 9

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

Question 10

what are four major phospholipids in plasma membranes

Answer 10

1)phosphotidylethanolamine
2)phosphotidylcholine
3)phosphotidylserine
4)sphingomylin (has choline)

Question 11

what are the charges of each of these lipids 1)phosphotidylethanolamine
2)phosphotidylcholine
3)phosphotidylserine
4)sphingomylin

Answer 11

1) 0
2) 0
3) -1
4) 0

Question 12

where would you find each of these lipids
1)phosphotidylethanolamine
2)phosphotidylcholine
3)phosphotidylserine
4)sphingomylin

Answer 12

1) and 3) in the inner membrane and 2) and 4) in the outer membrane (choline is usually on the outer membrane)

Question 13

where are the phosphocholine lipids more prevalent

Answer 13

outer membrane

Question 14

how do these phosphocholine lipids get to the ECM

Answer 14

flipase

Question 15

what happens if phosphatidylserine is exposed to the surface

Answer 15

it signals to the body that that cell is ready to die

Question 16

which P lipids contribute to the negative charge on the inner leaflet of the membrane

Answer 16

1) phosphotidylserine 2) phosphotidylinositol 3) phosphotidylphophatic acid

Question 17

what is the membrane potential

Answer 17

around -60 mv

Question 18

what is an action potential

Answer 18

the depolarization and repolarization of the cell membrane potential by influx and reflux of ions

Question 19

what causes an action potential

Answer 19

the influx and reflux of ions

Question 20

what are two functions of the membrane potential of the cell membrane

Answer 20

1. propagation of electrical impulses 2. battery, storage of energy

Question 21

what are proteins that go through the cell membrane called

Answer 21

transmembrane

Question 22

what are proteins that are hooks onto the outside of the membrane called

Answer 22

inosital bound proteins

Question 23

what are proteins that sit outside of the membrane called

Answer 23

peripheral proteins

Question 24

what is a translocon channel

Answer 24

protein that allows for the lateral movement of hydrophobic portions of a protein into the cell membrane

Question 25

name one other process structure that allows the lateral movement of hydrophobic protiens

Answer 25

lipid rafts by cholesterol

Question 26

what do lipid rafts move and how do they move them

Answer 26

they move GPI bound protein by increasing density relative to the raft

Question 27

what are lectins

Answer 27

proteins that can read the sugar code on certain proteins to see if theyre foreign or not

Question 28

what are integrins

Answer 28

proteins that help in the process of extravasation

Question 29

what is simple diffusion

Answer 29

movement from high to low conc doesnt need any help to move through membranr

Question 30

what is facilitated diffusion

Answer 30

passive movement of molecules along conc gradient its selective using its pores and carriers

Question 31

what is active transport

Answer 31

movement against the conc gradient and uses energy

Question 32

what are the three major facilitator of transport:

Answer 32

carriers, pores (transmembrane), and permeases (have various conformations)

Question 33

what are aquaporins

Answer 33

they are protein pores/water channels that increase water transport keeping the osmotic pressure. rapid transport of water

Question 34

what type of transport are aquaporins associated with

Answer 34

facilitative

Question 35

why must transporters be used to move ions across membrane

Answer 35

because membrane is greasy and hydrophobic while ions are charged and hydrophilic so they dont mix

Question 36

how does the structure of valinomycin antibiotic help it to transport ions across the membrane

Answer 36

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

Question 37

how do these ionophores kill bacteria

Answer 37

they disrupt the electrochemical gradient(membrane potential)