Chapter 9

Question 1

micelle

Answer 1

cone shaped, head greater than tail

Question 2

bilayer

Answer 2

cylindrical, head equals tail

Question 3

liposome

Answer 3

folded bilayer

Question 4

cellular membranes consists of….

Answer 4

• lipids

- membrane proteins

Question 5

Bimolecular reactions in membrane are more efficient than in….

Answer 5

solution

Question 6

Probability of molecular collision in 2D plane is _______ than in 3D space.

Answer 6

higher

Question 7

flippases

Answer 7

catalyze translocation of lipids from one side of bilayer to the other

Question 8

uncatalyzed translocation of lipids from one side of bilayer to the other is….

Answer 8

slow af

Question 9

below phase transition temperature, the membrane is…

Answer 9

in ordered paracrystalline state

Question 10

at temperatures above phase transition, membrane is….

Answer 10

fluid

Question 11

___________ is important for function

Answer 11

fluidity

Question 12

______________ of the phospholipids is adjusted for proper membrane fluidity.

Answer 12

fatty acid composition

Question 13

lipid raft

Answer 13

sphingolipids and cholesterol clustered together

Question 14

lipid rafts are stabilized by…

Answer 14

interactions between the cholesterol ring and one saturated hydrocarbon tails of sphingolipids

Question 15

lipids rafts function

Answer 15

attachment points for peripheral membrane proteins

Question 16

how do lipid rafts and membrane proteins attach?

Answer 16

two covalently attached saturated acyl chains or glycosylated phosphoinositol derivatives (GPI)

Question 17

intergral membrane proteins

Answer 17

usually span the bilayer with parts exposed on both sides; can be extracted with detergents

Question 18

peripheral membrane proteins

Answer 18

most in cytosol or extracellular space, some attached to membrane (non-covalent interaction or lipid anchors)

Question 19

proteins anchored to membrane by GPI are….

Answer 19

always outside the cell

Question 20

proteins anchored by fatty acyl or prenyl chains are ….

Answer 20

always inside the cell

Question 21

in intergral membrane proteins, charged residues are located mostly…

Answer 21

outside the membrane

Question 22

residues with _____________ dominate the inside

Answer 22

apolar side chains

Question 23

a-helical bundle

Answer 23

7 helices bonded together

Question 24

B-barrel

Answer 24

22 strands closing on itself (1 H bond…?)

Question 25

the __________ in the hydrophobic core of bilayer _______ regular secondary structures.

Answer 25

apolar environment, stabilizes

Question 26

membrane fusion

Answer 26

membrane vesicles that exist in cells fusing with plasma membrane and themselves (exocytosis, endocytosis, fusion of sperm and egg, cell division)

Question 27

How can a neutron cross the junction?

Answer 27

membrane vesicles full of Ace released to synaptic cleft, diffuse, interact with receptors, which serve as signal to open

Question 28

free energy equation for diffusion with both concentration and electric component

Answer 28

deltaG=-mFdeltaΨ +2.3RTlog[Cin]/[Cout]

Question 29

electric potential different favours movement of _ charge ions from _____ to _______

Answer 29

+, outside to inside

Question 30

electric potential different favours movement of _ charge ions from _____ to _______

Answer 30

+, outside to inside

Question 31

deltaG<0

Answer 31

favourable

Question 32

deltaG>o

Answer 32

unfavourable

Question 33

primary active transport

Answer 33

against electrochemical gradient

Question 34

secondary active transport

Answer 34

against electrochemical gradient, driven by ion moving down its gradient

Question 35

passive transport

Answer 35

transport down electrochemical gradient

Question 36

channels

Answer 36

can only transport molecules and ions down the electro gradient

Question 37

rate of transport though channel is ....

Answer 37

proportional to substrate concentration

Question 38

carriers

Answer 38

can catalyze both active and passive transport | -generally lower rate of transport than channels due to rate limiting step

Question 39

glucose transporter carrier equation

Answer 39

Vo=(Vmax[S]out)/(Kt+[S]out)

Question 40

polar side chins form __________ with glucose in transporter interior

Answer 40

hydrogen bonds

Question 41

uniport

Answer 41

passive carriers of one substrate

Question 42

symport

Answer 42

2 substrates in same direction

Question 43

antiport

Answer 43

2 substrate in opposite direction

Question 44

electroneutral

Answer 44

no net charge flow

Question 45

electrogenic

Answer 45

transports 1 charge across membrane

Question 46

ATP hydrolysis is...

Answer 46

highly exergonic reaction

Question 47

primary active transporters powered by ATP hydrolysis

Answer 47

Na+, K+, -ATPase

Question 48

large scale domain movement are involved in ion transport by...

Answer 48

Ca+2-ATPase

Question 49

which allow greater freedom of movement... a-helical or B-barrel?

Answer 49

a-helical

Question 50

ATP synthase

Answer 50

convert energy of proton gradient to make ATP | -reversible

Question 51

secondary active transporters operate by..

Answer 51

rocket switch mechanism

Question 52

how does the rocket switch mechanism operate

Answer 52

exposing the binding site from cytoplasm (state I) to extracellular space (state II) is triggered by protonation and deprotonation of charged residues in the interior

Question 53

transition between two states in rocket switch mechanism requires...

Answer 53

binding affinity of state I to be lower than state II

Question 54

Na+K+ ATPase hydrolyzes ATP and that energy is ...

Answer 54

used to pump sodium ions out of the cell and potassium ions in

Question 55

3 important properties of protein ion channels

Answer 55

- high conduction rates - selectivity - gating