Biology Test 2 Flashcards

Front 1

Membranes are ___ barriers

Back 1

selective

Front 2

internal membranes

Back 2

enclose an intracellular compartment

Front 3

Membrane composition (2)

Back 3

lipids and proteins

Front 4

3 types of lipids in membrane

Back 4

phospholipids (most abundant) glycolipids (sugar part of head group) and sterols

Front 5

2 types of proteins in membrane

Back 5

integral and peripheral

Front 6

integral protein meaning

Back 6

directly attached to membrane

Front 7

peripheral protein meaning

Back 7

loosely associated with membranes

Front 8

Proteins take up _ of mass of membrane

Back 8

50%

Front 9

amphipathic phospholipids form a ____

Back 9

lipid bilayer

Front 10

will a phospholipid bilayer spontaneously rearrange to elminate free edges?

Back 10

yes

Front 11

liposomes and vesicles have a _ and an aqueous ____

Back 11

phospholipid bilayer and interior

Front 12

membranes behave as a two dimensional fluid _____

Back 12

molecules move

Front 13

is fluidity the same as flexibility?

Back 13

nope

Front 14

Factors affecting membrane fluidity

Back 14

phospholipid composition (fatty acid chain and saturation)

sterols (cholesterol)

Front 15

Fatty acid chain length how does it affect membrane fluidity

Back 15

short chains increase fluidity

Front 16

fatty acid chain length saturation how does it affect membrane fluidity

Back 16

double bonds increase fluidity

Front 17

cholesterol how does it affect membrane fluidity

Back 17

more cholesterol decreases fluidity since it adds rigidity

Front 18

cholesterol ___spaces in the bilayer and makes the bilayer ____

Back 18

fills, more rigid

Front 19

is cholesterol amphipathic?

Back 19

yes

Front 20

are membranes assymetrical?

Back 20

yes

Front 21

when is membrane symmetry established?

Back 21

synthesis at the ER

Front 22

Do flippases have specificity for different types of phospholipids?

Back 22

yes

Front 23

T/F? new lipids are added to both sides of the membrane

Back 23

false

Front 24

does the cytosolic face remain to cytosol and vice versa always?

Back 24

true

Front 25

membrane proteins carry out most membrane functions ______

Back 25

true

Front 26

B barrel

Back 26

spans the membrane, large curved B sheet

Front 27

in B barrel does the outside not have to be nonpolar

Back 27

false, it has to be amino acid has to be nonpolar

Front 28

detergents

Back 28

are used to separate integral membrane proteins from the lipid bilayer

Front 29

3 properties of detergents

Back 29

amphipathic, single hydrophobic chain, do not form bilayers

Front 30

what kind of membrane in detergents?

Back 30

monolayer micelle

Front 31

solubilization of integral membrane proteins with _____

Back 31

detergents

Front 32

micelle

Back 32

single layer arrangement

Front 33

cell surfaces are coated with ____

Back 33

carbohydrate

Front 34

carbohydrate layer composition

Back 34

glycoprotein, proteoglycan, glycolipid

Front 35

glycoprotein

Back 35

protein with short, covalently attached oligosaccharide

Front 36

proteoglycan

Back 36

protein with one or more long oligosaccharides

Front 37

glycolipid

Back 37

lipid with covalently attached oligosaccharide

Front 38

carbohydrate layer function

Back 38

protection from chemical and mechanical damage (lubrication)

cell-cell recognition (lectins)

Front 39

lectins

Back 39

proteins that bind oligosaccharide chains

Front 40

sugars are always to __ side of membrane

Back 40

extracellular

Front 41

lectin binding is responsible for recruitment of ____ to sites of infection

Back 41

white blood cells

Front 42

are all proteins freely diffusible in the membrane?

Back 42

some but not all

Front 43

what do these pattern reveal bout proteins?

Back 43

-all hydrophobic since in membrane
-proteins have different
-not all diffuse through membrane
-not all equilly mobile

Front 44

not all proteins are mobile some are restricted to _____

Back 44

membrane domains

Front 45

cell cortex is ___

Back 45

framework of proteins (largely spectrin) that attaches to membrane proteins, restricting their mobility

Front 46

tight junctions preserve ___

Back 46

the assymetric distribution of membrane proteins

Front 47

transporter

Back 47

moving parts, can shift small molecules from one side of the membrane to the other by changing its shape

Front 48

channel

Back 48

form tiny hydrophillic pores in the membrane through which solutes can pass by diffusion, most channels are ion channels because they let through inorganic ions only

Front 49

ion channels

Back 49

let through inorganic ions only

Front 50

what is the most plentiful positively charged ion (cation) outside a cell and which one is the inside of the cell

Back 50

outside is NA+
inside is K+

Front 51

Lipid bilayers are impermeable to ____

Back 51

solutes and ions

Front 52

channels discriminate against ___

Back 52

basis of size and electric charge, if a channel is open and ion or molecule that is small enough and carries an appropriate charge can slip through

Front 53

transporters discriminate against ___

Back 53

only to those molecules or ions that fin into a binding site on the protein, then transfers these molecules across the membrane one at a time by changing its own conformation, bind to their solutes with great specificity

Front 54

transport pump

Back 54

drive species against the concentration gradient always couples with some other process that provides energy usually gained from another concentration gradient

Front 55

Fluid Mosaic Model

Back 55

Cell membrane is a "mosaic" of lipids and proteins

Front 56

T/F a phospholipid bilayer will spontaneously rearrange to form a circle

Back 56

True...wants to eliminate free edges

Front 57

4 types of proteins and describe them

Back 57

integral-transmembrane, membrane-associated, lipid-linked....peripheral are protein attached

Front 58

Only way that an integral membrane protein can be removed from membrane...and peripheral membrane proteins can be remove by ____

Back 58

detergents....more gentle extraction methods

Front 59

Sugars on extracellular surface help with ___ and ____

Back 59

protection and recognition

Front 60

2 experiments that proved that proteins move around

Back 60

the mouse/human protein dye experiment and the tracking of proteins...shows that some move a lot and some move not as much

Front 61

ways that proteins are not mobile (4)

Back 61

1)tethered to cell cortex
2) tethered to extracellular matrix
3) cell-cell adhesion
4)tight junctions

Front 62

Describe the glucose/sodium tight junction picture/diagram

Back 62

Glucose due to tight junctions can go from a lower concentration to higher concentration and glucose can leave cell just in case [glucose] is TOO high, transporter makes glucose go back and forth between inside and outside cell so [glucose] is high inside cell

The sodium gradient takes glucose along for the ride and the tight junctions prevent glucose from flowing freely out of the cell

Front 63

Understand the Structural features and components of membranes

Back 63

check

Front 64

be able to explain how membranes are formed in a eukaryotic cell

Back 64

check

Front 65

be able to compare/contrast ways in which membrane proteins associate with lipid bilyaers

Back 65

check

Front 66

be able to explain how cells restric the movement of membrane proteins

Back 66

check

Front 67

Phosphatidylcholine___

Back 67

is the most common phospholipid in cell membranes

Front 68

inositol phospholipids

Back 68

lipids in membrane that face the cytosol

Front 69

understand the basis for selective membrane permeability

Back 69

u

Front 70

understand the difference between simple diffusion, facilitated diffusion, and active transport

Back 70

d

Front 71

know the classes of membrane transport proteins and the mechanisms involved in their function

Back 71

d

Front 72

Diffusion of molecules across a synthetic lipid bilayers is dependent on ____ and ___ (lipid)

Back 72

size and solubility

Front 73

Do charge molecules diffuse across a membrane?

Back 73

no they don't diffuse...well rarely

Front 74

____ are responsible for the ___ transfer of water-soluble molecules (___) across the membrane

Back 74

membrane transport proteins, selective, solutes

Front 75

selective transport can lead to the ____ inside and outside the cell (and als between the ___ and ____)

Back 75

differential distribution, cytosol and organelles

Front 76

Why have channels if still will diffuse across membrane?

Back 76

speeds it up

Front 77

mechanisms of solute discrimination (2)

Back 77

carrier proteins and channels

Front 78

transport energetics (2)

Back 78

passive, active

Front 79

Channels only function ____ their concentration gradient

Back 79

down

Front 80

carriers can be ___ and __ while channels are ____ only

Back 80

passive/active and passive

Front 81

membrane transporters in passive transport increase the ___ of diffusion

Back 81

rate

Front 82

why does the rate of facilitated diffusion plateau?

Back 82

THe enzyme is saturated and the concentration gradient isnt pushing it to go through as intensely quickly

Front 83

is the passive transports of uncharged molecules reversible?

Back 83

yes

Front 84

for an ___ molecules glucose, the diretion of transport is depenedent solely on concentration

Back 84

uncharged

Front 85

membrane potential (E)

Back 85

cell membrane with voltage across them called which exerts a force on charged molecules

Front 86

electrochemical gradient

Back 86

net driving force, sum of the concentration and electrical forces

Front 87

membrane potential typically in a cell is ___ on the inside

Back 87

negative

Front 88

active tranport is the transport of solutes ____ their electrochemical gradient

Back 88

against

Front 89

3 mechanisms of active transport

Back 89

coupled transporter, atp-driven pump, light-driven pump

Front 90

active transport: ___ driven pumps...give example

Back 90

ATP...sodium potassium pump

Front 91

ATPase

Back 91

pump requiring atp to function

Front 92

NA+-K+ ATPase does what to a membrane potential

Back 92

establishes it

Front 93

describe Na+-K+ ATPase

Back 93

done

Front 94

2 types of coupled transporters

Back 94

symport and antiport

Front 95

symport and anitport and uniport describe

Back 95

both, opposite, one thing

Front 96

The ___ gradient generated by the Na+-K+ pump is used in animal cells as an energy source to drive transport of many other solutes by coupled transport

Back 96

Na+

Front 97

The ___ transport of glucose can be driven by the downhill transport of ____

Back 97

na+

Front 98

can you use both active and passive transport mechanisms on the same solute in one cell? how?

Back 98

yes...assymetric distribution of transport proteins

Front 99

The Na+-K+ pump also helps maintain ____ balance

Back 99

osmotic

Front 100

A signal is communicated as a change in ___

Back 100

membrane potential

Front 101

ion channels (3)

Back 101

selective, gated, passive transport

Front 102

ion channels can be selective by (2)

Back 102

charge, size

Front 103

channels flicker between ___ and ___ states

Back 103

closed, open

Front 104

process called ___ opens the channel so current can flow

Back 104

gating

Front 105

patch-clamp recording

Back 105

measures current through a single ion channel

Front 106

ion channels are___-triggered by a specific stimulus (list 4)

Back 106

gates
voltage gated, ligand gated (intracellular and extracellular) and stress-gated

Front 107

different ___ concentrations on either side of the lipid bilayer results in the ___ potential

Back 107

ion, membrane

Front 108

____ help maintain the membrane potential

Back 108

K+ leak channels

Front 109

Sodium will always give a you a ___ membrane potential while potassium will ___

Back 109

positive, negative

Front 110

know the structural components of a nerve cell

Back 110

done

Front 111

understand how an action potential is initiated and transmitted to a target cell

Back 111

done

Front 112

understand how electrical signals can be converted into chemical signals and back again to electrical signals

Back 112

done

Front 113

recognize the simliratiy to the free energy equation relating to differential concentrations across a membrane, and how charge affects this potential energy

Back 113

done

Front 114

A signal is communicated as a ____ in ____

Back 114

change in membrane potential

Front 115

a stimulus causes a ____ membrane depolarization

Back 115

localized

Front 116

A localized membrane depolarization large enough to pass a critical ____ will activate ____ _____

Back 116

threshold, voltage-gated Na+, channels

Front 117

Na+ flood into the cell, further depolarizing the membrane this is called an ___ ____

Back 117

action potential

Front 118

note that the membrane becomes _____

Back 118

re-polarized

Front 119

After the membrane is fully depolarized, voltage-gated Na+ channels adopt an ___ conformation-even though the membrane is still depolarized

Back 119

inactivated

Front 120

How is the membrane re-polarized? (3)

Back 120

1) Voltage-gated Na+ channels are inactivated
2) Voltage-gated K+ channels are activated
3) K+ leak channels continue to function

Front 121

an action potential can spread long distances by ___ neighboring regions of the membrane

Back 121

depolarizing

Front 122

what controls the direction of the signal in nerves?

Back 122

membrane potential and the switching to an inactivated stage

Front 123

neurons in vertebrates have a ____ which allows much faster propogation of an action potential

Back 123

myelin sheath

Front 124

multiple sclerosis

Back 124

autoimmune disorder resulting in the gradual destruction of the myelin sheath

Front 125

what is the gap between nerve cells called?

Back 125

synaptic cleft

Front 126

the action potential cannot cross a ____

Back 126

synapse

Front 127

the ___ is converted to a ___ signal at a nerve terminal

Back 127

electric to chemical

Front 128

A ___ is converted back into a ____ by ____

Back 128

chemical, electrical, transmitter-gated channels

Front 129

neurotransmitters must be quickly removed from the synaptic cleft to ensure that the postsynaptic cells return to their ___

Back 129

resting state

Front 130

Review of what happens when an action potential reaches an axon terminal (4)

Back 130

1)an action potential cannot cross a synapse so the electrical signal is converted to a chemical signal, neurotransmitters stored in synaptic vesicles
2) the action potential activated the voltage-gated Ca 2+ channels in the nerve terminal
3) the Ca 2+ influx triggers the fusion of synaptic vesicles with the plasma membrane, releasing the stored neurotransmitters into the synaptic cleft
4) neurotransmitters bind to receptros (ligand-gated ion channels) on the target cell (postsynaptic cell) and initiate a new action potential

Front 131

neaurotransmitter receptors are __ ___ channels

Back 131

gated ion

Front 132

excitatory neurotransmitters

Back 132

initiate an action potential

Front 133

inhibitory neurotransmitters

Back 133

prevent action potential

Front 134

chlorine channels are ___ neurotransmitters

Back 134

inhibitory

Front 135

sodium channels are ___ neurotransmitters

Back 135

excitatory

Front 136

the ___ is one of the best studied transmitter-gated ion channels and it is involved in___

Back 136

acetylcholine.....neuromuscular junciton