Physiology - Membrane

Front 1

3 Classes of membrane lipids

Back 1

phospholipids (70-75%)
cholesterol (20-25%)
glycolipids (2-3%)

Front 2

subclasses of phospholipids

Back 2

choline-phospholipids: phosphatidyl-choline, sphingomyelins

amino-pholipids: phosphatidylserine

Front 3

function of cholesterol and saturated FA chains

Back 3

adds stiffness, decrease membrane fluidity

Front 4

where's glycolipids located

Back 4

outer leaflet

Front 5

where are phosphatidylserine and phosphatidylinositol

Back 5

inner leaflet

Front 6

where's sphingomyelin

Back 6

external, some internal leaflet

Front 7

the composition of membrane rafts and it's function

Back 7

clusters of cholesterol, proteins sphingolipids

rafts provide island to cluster key signaling components, internalization with caveolae

Front 8

functions of membrane proteins

Back 8

transport (pumps/carrier/channels)
structural - anchors, maintain membrane integrity
receptors/signaling
enzymes
glycoproteins - Ab recognition

Front 9

types of membrane transport

Back 9

diffusion
facilitated diffusion - channel, carrier
active transport - primary, secondary

Front 10

random thermal Brownian motion

Back 10

allow diffusion of molecules

Front 11

Fick's First Law of Diffusion

Back 11

J = -DA(dC/dX)
J - net rate of diffusion on moles or grams/time;
D - diffusion coefficient of the solute
A - area of the membrane
dC - concentration difference across the membrane
dX - membrane thickness

Front 12

D - diffusion coefficient of the solute, is inversely proportional to size and charge of particle and viscosity of solvent? (1/D)

Back 12

T

Front 13

permeability across membrane depend on ... (4)

Back 13

size, charge, lipid solubility, membrane thickness

Front 14

Facilitated diffusion, carrier proteins, transport solute via

Back 14

ping-pong conformational change

Front 15

Can facilitated diffusion and active transport reach Vmax?

Back 15

Yes, b/c they are similar to enzyme

Front 16

Facilitated diffusion and active transport exhibits 3 properties.

Back 16

chemical specificity, stereospecificity, competitive inhibition

Front 17

In simple diffusion, the greater the concentration difference, the ____ the rate of diffusion.

Back 17

faster the rate of diffusion

Front 18

the ion channel can be triggered open by .... (3)

Back 18

voltage, ligands, stretch

Front 19

1. primary active transport uses ___ as energy
2. secondary active transport couples

Back 19

1. ATP
2. energy from gradients

Front 20

examples of primary active transport, and its role

Back 20

Na-K ATPase, moves 3Na+ out and 2K+ in. set up gradient across the membrane.

v-HATPase. moves H+ across gradient.

Front 21

Steps of Na+ and K+ transport by Na-K ATPase

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1.Binding of 3 Na+ inside
2.Hydrolysis of ATP for energy
3.Release of Na+ outside
4.Binding of 2 K+ outside
5.Dephosphorylation
6.Release of K+ inside

Front 22

what chemical blocks Na-K ATPase? Which part of the pump does the chemical exhibit its effect? What is the effect on the heart?

Back 22

oubain - digitalis glycosides
oubain binds extracellular side
It slows heart rate - treat atrial fibrillation.

Front 23

v-HATPase function on bone and stomach.
What will happen if vHATPase are blocked with bafilomycin?

Back 23

It enhances bone resorption, and reduce acid release in the the stomach.
Inhibition will block tooth eruption

Front 24

Subsets of secondary active transport.

Back 24

symport and antiport

Front 25

example of symporter. how many Na+ are translocated per cycle.

Back 25

Na/aa symport. 2 Na+ are translocated.

Front 26

example of antiporter, and its functions

Back 26

Na+/H+ antiporter, drives proton out of the cell.

Front 27

Steps of transport of glucose from gut lumen into extracellular fluid. (active transport and facilitated diffusion)

Back 27

Intestinal epithelium: [glucose] higher in than out
1. Na+ gradient established using primary active transport – ATP hydrolysis powers Na/K pump
2. Use energy of Na+ to get glucose into the cell using secondary active transport
3. Let glucose flow out down the gradient through carrier using facilitated diffusion

Front 28

Osmotic pressure

Back 28

pressure needed to stop water movement.

Front 29

osmolarity goes down refer to ...

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in hypotonic solution

Front 30

Osmotic pressure equation

Back 30

p = RTfic
p - osmotic pressure
RT - 22.4 atm
f - osmotic coefficient
i - number of ions formed by dissociation of solute
c - molar concentration of solute

Front 31

Ions have both ____ and ____ gradients that must be balanced at equilibrium

Back 31

electrical, chemical

Front 32

chemical energy equation
electrical energy equation

Back 32

Chem energy F = -RT ln([G]i/[G]o)

Electrical energy F = zFV
z = charge
F = Faraday constant
V = voltage

Front 33

Nernst equation

Back 33

Front 34

Ek in Nernst eqation is

Back 34

Vm when major ions are at equilibrium, the potential at which there's no net movement of ions for the given intracellular and extracellular concentrations

Front 35

typical cells' membrane potential at rest is at what range?

Back 35

-50mV ~ -80mV

Front 36

Which ions contribute to the membrane potential?

Back 36

Na+, Cl-, K+, Mg++, Ca++

Front 37

the more permeable the ion X, the ___ it contributes to the membrane potential

Back 37

the more

Front 38

in resting cell, ___ has the biggest influence on membrane potential, since it has the largest P.

Back 38

K+ (or Cl-)

Front 39

In resting cell, Vm is close to

Back 39

Ek (equilibrium potential for K+)

Front 40

when Vm = -60mV, resting membrane potential, are ions at equilibrium?

Back 40

no, energy are required to pump ions against their concentration gradient

Front 41

Goldman-Hodgkin-Katz (GHK) equation

Back 41

P = permeability coefficient

Front 42

what sets resting membrane potential?

Back 42

negatively charged proteins - impermeable

Na+-K+ pump - maintains gradients

large K+ conductance (leak K+ currents add to negative membrane potential) - Vm near Ek

Front 43

impermeable intracellular anionic proteins will have what kind of effect of ions and water

Back 43

cations will be attracted inside of the cell to balance out the charge, will allow water to move in by osmosis.

Front 44

a small change in ion concentration makes a big change in membrane voltage. T/F

Back 44

T

Front 45

voltage ion channel structure

Back 45

each domain has 6 segments span the membrane.

4 subunits (domains) create a pore

Front 46

key characteristics of ion channels ... (4)

Back 46

gating, permeation/selectivity, inactivation, block

Front 47

Gating of ion channels are mediated by (3)

Back 47

secondary messenger (Ca2+), neurotransmitter, voltage change

Front 48

how do ion channel discriminate against ions (permeation/selectivity)?

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size of the ions, charge of the ion, and molecular interaction along the wall of the channel.
selectivity filter (close to extracellular space) bind to their ions.

Front 49

conductance of ion channels are

Back 49

how quickly ions moving through the channel.

Front 50

the more rapidly the ion move through the ion channel, ___ the conductance and ___ IpA

Back 50

higher and higher

Front 51

2 ways to increase total current across membrane

Back 51

increase number of channels open

increase the amount of time each channel is open

Front 52

How is ion channels gated?

Back 52

Ball and chain model of inactivation: positive protein loop moves into region exposed when voltage gates channel open.

Front 53

tetradotoxin (TTX) blocks ___ channels

Back 53

Na+ channel blocker

Front 54

function of lidocaine derivative (QX-222) on ion channels

Back 54

channel closes most of the time

Front 55

effect of local anesthetics on ion channels

Back 55

block movemnent of ions through pores

Front 56

Ena
Ek
Ecl
Eca

Back 56

= + 60 mV
= – 86 mV
= – 68 mV
= + 125 mV