Membrane Structure

Question 1

membrane lipids include _

Answer 1

glycerophospholipids, cholesterol, and sphingolipids

Question 2

biological membrane key properties

Answer 2

two-dimensional fluid and low permeability to water-soluble molecules and ions

Question 3

low solubility is key to _

Answer 3

ATP generation, synaptic transmission, senses

Question 4

cell membrane composition

Answer 4

lipids (42%), proteins (55%), cholesterol (3%)

Question 5

triacylglycerol vs. glycerolphospholipids

Answer 5

fatty acids are hydrophobic but glycerolphospholipids have a polar head group

Question 6

glycerol phospholipids

Answer 6

have a polar head group and two hydrophobic fatty acid tails –> leads to lipid bilayer

Question 7

phosphatidylcholine is most abundant in _

Answer 7

mitochondrion and ER

Question 8

phosphatidylcholine is least abundant in _

Answer 8

myelin and RBC membrane

Question 9

phosphatidylserine

Answer 9

low amounts in most membranes

Question 10

phosphatidylethanolamine is most abundant in _

Answer 10

mitochondrion

Question 11

general structure of glycerophospholipids

Answer 11

glycerol backbone + saturated fatty acid tail + unsaturated fatty acid tail + polar head group

Question 12

sphingolipid structure

Answer 12

sphingosine back bone + fatty acid + polar head group

Question 13

four major phospholipids in cell membranes

Answer 13

phosphatidylcholine, phosphatidylserine, phosphatidylethanolamine, sphingomyelin

Question 14

phosphatidylinositols

Answer 14

not abundant but important for creating DAG and IP3 for cell signaling and assigning membrane identities

Question 15

DAG

Answer 15

activated PKC

Question 16

IP3

Answer 16

releases intracellular Ca+2 stores

Question 17

membrane identities

Answer 17

different PI’s in different stages of endosome to signal which molecules are going to fuse

Question 18

glycolipids are most abundant in _

Answer 18

myelin (in brain)

Question 19

cholesterol is most abundant in _

Answer 19

liver PM, RBC PM, and myelin

Question 20

lateral diffusion

Answer 20

very rapid

Question 21

unsaturation _

Answer 21

increases fluidity

Question 22

cholesterol _

Answer 22

decreases fluidity

Question 23

floppase

Answer 23

transports from inside to outside

Question 24

flippase

Answer 24

transports from outside to inside

Question 25

extracellular space phospholipids

Answer 25

heads of phosphatidylcholine and sphingomyelin

Question 26

cytosol phospholipids

Answer 26

heads of phosphatidylserine and phosphatidylethanolamine

Question 27

How are proteins restricted to specific domains and surfaces?

Answer 27

restrict diffusion with tight junctions, lipid rafts, and polarized epithelium

Question 28

lipid rafts

Answer 28

cholesterol and sphingolipid-rich membranes that float freely within the liquid-disordered bilayer

Question 29

lipid raft function

Answer 29

protein concentration, alter protein function, targeting of cytoskeleton, site of endocytosis, and signaling

Question 30

membrane proteins

Answer 30

ion channels/pores, carriers/transporters, receptors, enzymes, and adhesion molecules

Question 31

carbohydrates

Answer 31

vesicle trafficking results in placement on exterior of cell

Question 32

glycocalyx

Answer 32

carbohydrate rich zone at cell surface