B2.081 Prework 1 The Fluid Mosaic Model

Question 1

what are the 6 properties of membranes?

Answer 1

1. components: lipids and proteins
2. amphipathic
3. noncovalent assembly
4. sheetlike
5. fluid
6. asymmetric

Question 2

what are the two classes of phospholipids?

Answer 2

derivatives of glycerol or sphingosine

Question 3

what are the components of a glycerol derived phospholipid?

Answer 3

2 fatty acid tails
glycerol
phosphate
alcohol

Question 4

saturated vs. unsaturated fatty acids

Answer 4

saturated = single bonds, staggered
unsaturated = double bonds, kinked at double bond locations

Question 5

what do alcohols attached to phosphatidate have in common?

Answer 5

charged, polar, or aromatic

Question 6

what is a phosphatidate

Answer 6

phospholipid without alcohol group

Question 7

what are the components of a sphingosine derived phospholipid?

Answer 7

sphingosine
fatty acid
sugar

Question 8

what is the simplest glycolipid?

Answer 8

sphingosine
fatty acid
glucose

Question 9

what are gangliosides?

Answer 9

sphingosine lipids with many sugar residues

Question 10

what happens to amphipathic lipids in water

Answer 10

they assemble into noncovalent structures
monolayer
bilayer
liposome
micelle

Question 11

what is the function of cholesterol?

Answer 11

modulates membrane flexibility/fluidity

Question 12

what are the types of membrane proteins?

Answer 12

integral
peripheral
lipid-modified

Question 13

how are protein islands formed?

Answer 13

integral proteins shift laterally due to binding of signaling proteins

Question 14

how does the membrane mediate cell shape changes?

Answer 14

membrane proteins interact with the cytoskeleton forming a mesh pattern

Question 15

what are cytoskeleton corrals?

Answer 15

limits where membrane proteins can travel by preventing lateral motions

Question 16

what are some sources of membrane asymmetry?

Answer 16

free lateral diffusion
leaflet composition difference
transverse motions of lipids needs protein

Question 17

where are new lipids synthesized?

Answer 17

intracellularly

Question 18

what happens when a bulge is created from new lipids in the inner leaflet?

Answer 18

nonspecific lipid transporter flips some lipids into the outer leaflet
asymmetry is abolished

Question 19

what restores membrane asymmetry after lipid movement?

Answer 19

flippase- move things to the inner leaflet

floppase- move things to the outer leaflet

Question 20

where do cholesterol rafts accumulate?

Answer 20

outer leaflet

Question 21

where are glycol-moieties located?

Answer 21

exoplasmic

either outside a cell or inside an organelle