Exam 1 Part 6

Question 1

functions of membranes in cells

Answer 1

1. barrier/boundary (protection)
2. area for localization of proteins
3. areas of localized communication
4. import/export
5. movement

Question 2

animal membrane makeup

Answer 2

40% lipids
50% proteins
10% carbohydrates

Question 3

how membranes change fluidity

Answer 3

change saturation and unsaturation of lipid tails with dB

Question 4

formation of sealed compartments

Answer 4

planar phospholipid bilayer with edges exposed to water

self-sealable because of energies

Question 5

membrane movements

Answer 5

lateral movements, rotations, bending

flip-flops are rare without enzymes

Question 6

fluidity of membrane depends upon

Answer 6

1. bonds
2. FA tail lenght (shorter, more fluid, longer, more viscious)
3. amount of cholesterol

Question 7

cholesterol

Answer 7

can fit in between unsaturated area which can make it more viscious

Question 8

lipid rafts

Answer 8

localization sites
keeps stuff all in the same area
pack stuff that need to be in one area together
makes membrane asymmetric

Question 9

synthesis of membranes…

Answer 9

start in endoplasmic reticulum

Question 10

scramblase

Answer 10

moves random phospholipids from one ER membrane side to the other

Question 11

Flippase

Answer 11

transfers specific phospholipids from Golgi membrane side to cytosolic side
-leads to asymmetry

Question 12

membrane protein types

Answer 12

transporters and channels
anchors
receptors
enzymes

Question 13

transporters and channels

Answer 13

allow things to pass through membrane like glucose, ions, a.a.,metabolites

Question 14

anchors

Answer 14

anchors things like actin to a specific area

Question 15

receptors

Answer 15

receive hormones, neurotransmitters on the surface of the membrane

Question 16

enzymes

Answer 16

involve signalling in the cell

Question 17

hydropathy plot

Answer 17

based on whether R groups are hydrophobic or hydrophilic

Question 18

how membranes associate with the membrane

Answer 18

transmembrane
monolayer-associated a-helix
lipid-linked
protein-attached

Question 19

cell cortex

Answer 19

fibers that hold up the membrane

Question 20

glycocalyx

Answer 20

carbohydrates surrounding the cell

Question 21

functions of carbohydrate layer

Answer 21

lubrication
protection
recognition

Question 22

when studying cell membranes…

Answer 22

you need to hide hydrophobic regions so that they go into solution

Question 23

FRAP

Answer 23

Fluorescence recovery after photobleaching

Question 24

SPT

Answer 24

single particle tracking