Topic 6

Question 1

Lipids

Answer 1

nonpolar, hydrophobic, insoluble in water

Question 2

examples of lipids

Answer 2

fatty acids, triglycerols, membrane lipids, chloesterol

Question 3

fatty acid

Answer 3

long chains of hydocarbon carboxylic acids 
amphipathic
saturated (no double bonds)or unsaturated (double bonds)

Question 4

double bonds are usually in ___ conformation, why

Answer 4

cis, lowers melting point by introducing kinks in structure

Question 5

how to name fatty acids

Answer 5

number of carbons: number of double bonds (if trans, put trans here) triangle number at which double bond is

Question 6

number of cis bonds increase, MP ___

Answer 6

lowers, more liquid are room temp

Question 7

what affects fatty acid melting point

Answer 7

length and saturation

Question 8

longer fatty acid tails have ___ MP, shorter have ___

Answer 8

higher, lower

Question 9

saturated fatty acids have ____ MP, shorter have ____

Answer 9

higher, lower

Question 10

which one takes precedence? length or unsaturation

Answer 10

usaturation

Question 11

do cis or trans fatty acid stack better

Answer 11

trans

Question 12

TAG

Answer 12

tricyglycerol, stores fatty acids, very hydrophobic,

Question 13

membrane lipids

Answer 13

glycerophospholipds, sphingolipids, cholesterol

Question 14

glycerophospholipids

Answer 14

strongly amphipathic (large polar group compared to TAG)

Question 15

Cholesterol

Answer 15

rigid, non-polar, weakly amphipathic, mostly hydrophobic

Question 16

T/F does cholesterol from membrane alone?

Answer 16

OH associated with polar headgroups and nonpolar portion inside membrane

Question 17

amphipathic molecules form ___ or ___ in water

Answer 17

micelles (fatty acids) and bilayers (membrane lipids)

Question 18

liposomes

Answer 18

the spherical vesicles that lipid bilayers form

Question 19

Bilayers

Answer 19

acyl chain and polar head group, non-covalent, fluid yet stable

Question 20

Transition temperature ____ artificial membrane

Answer 20

very sharp unlike biological membrane not sharp

Question 21

DTUS

Answer 21

decreasing temp, more unsaturated, shorter fatty acids

Question 22

ITSL

Answer 22

increasing temp, saturated, longer fatty acids

Question 23

cholesterol limits ___

Answer 23

rotational movement, increasing van der walls

Question 24

cholesterol in low temp

Answer 24

prevents membrane from packing too close

Question 25

cholesterol in high temp

Answer 25

decreases motion and disorder, increases rigidity

Question 26

lipids move which way in a membrane

Answer 26

laterally

Question 27

how can transverse diffusion happen

Answer 27

flipases increase rate of transversion diffusion by specific transport

Question 28

Types of membrane proteins

Answer 28

Integral, peripheral, lipid linked

Question 29

integral

Answer 29

hydrophobic interactions, polar on the outside, non polar inside, look like dumbell

Question 30

peripheral

Answer 30

on the perimeter, electrostatic and polar, easy to separate from membrane,

Question 31

lipid linked

Answer 31

hydrophobic with lipid prosthetic group anchor

Question 32

how can the middle portion of peripheral membranes be hydrophobic

Answer 32

they have hydrophobic amino acid tails pointing out on the surface

Question 33

example of K+ channel

Answer 33

non polar side chains are in the middle and polar on es on the outisde

Question 34

examples of polar side chain amino acids on the outside

Answer 34

Asp, Glu, Lys, Arg

Question 35

secondary structures that cross membranes

Answer 35

a-helix (must be 20 or more hydrophobic aa to cross membrane) and beta barrels

Question 36

Fluid Mosaic Model

Answer 36

lipids move laterally not transverse, limited by cytoskeleton, carbohydrate chains attached to extracellular cellular surface

Question 37

which molecules diffuse

Answer 37

small non polar molecules

Question 38

what does rate of diffusion depend on

Answer 38

size of molecule (small move faster), concentration gradient (larger gradient increases rate), lipid solubility (greater solubility rate increases)

Question 39

passive transport

Answer 39

exergonic, energy released

Question 40

active transport

Answer 40

energy required, endergonic

Question 41

if G is -

Answer 41

spontaneous, passive

Question 42

if G is +

Answer 42

needs energy, non spont

Question 43

overall G must be ___ for transport to occur

Answer 43

-

Question 44

what do transport proteins do

Answer 44

reduce activation energy barrier for transport

Question 45

examples of passive transport

Answer 45

porins and ion channels

Question 46

porins

Answer 46

beta barrel, water-filled pore in center, trimer, non selective

Question 47

ion channels

Answer 47

tetramers, channel between subunits, highly selective

Question 48

K+ ion channel, why does K+ pass through more easily than Na+

Answer 48

cant interact as well as K+ in channel, not about size

Question 49

Transporter proteins (5)

Answer 49

type of transport protein, do NOT span across membrane, conformational change allows passage, passive or active, selective

Question 50

curve for passive transport by carrier proteins for velocity vs solute

Answer 50

hyperbolic

Question 51

carrier proteins are

Answer 51

uni/sym/anti port

Question 52

primary active transport

Answer 52

uses ATP, selective

Question 53

secondary active transport

Answer 53

uses ion gradient as source of free energy

Question 54

Na+K+ ATPase

Answer 54

primary active transporter, concentration gradients generated are used as energy source, electrogenic, antiport

Question 55

how is activity determined:

Answer 55

by size of concentration gradient

Question 56

steps of Na+K+ ATPase

Answer 56

1) 3 Na+ enters from inside
2) ATP phosphorylated causing conformational change
3) Na+ released outside
4) 2 K+ comes from outside
5) hydrolysis of Pi causes conformational change
6) K+ released inside

Question 57

Na Glucose transporter

Answer 57

secondary active symporter