1.3

Question 1

Cell membrane fxn

Answer 1

separates inner contents of a cell from the outside environment and decides what can pass in or out

Question 2

______ determine most of the membranes specific fxns

Answer 2

proteins

Question 3

Plasma membrane fxns (3)

Answer 3

selectively permeable barrier, communication, allows compartmentalization and separation

Question 4

Lipid bilayer

Answer 4

membrane lipids form bilayers in water, asymmetrical

Question 5

fluidity of lipid bilayer depends on ________

Answer 5

composition

Question 6

cell membrane composition

Answer 6

40% lipids, 60% proteins, 1-10% carbohydrates

Question 7

2 types of phospholipids

Answer 7

glycerophospholipids, sphingolipids

Question 8

Membrane lipids are amphipatic, meaning?

Answer 8

have both hydrophillic and hydrophobic groups

Question 9

saturated fatty acids ______ have double bonds

Answer 9

DO NOT

Question 10

fatty acids the body cannot synthesize?

Answer 10

essential fatty acids

Question 11

triglycerides (from? fxn? composition?)

Answer 11

fat from the food we eat (butter, oil)
store energy, produce energy, insulation
3 fatty acids + 3 alcohol groups

Question 12

phosphoglycerides

Answer 12

glycerol + 2 fatty acids + head groupss

Question 13

most abundant phospholipid in cell membranes

Answer 13

phosphatidylcholine (sat at sn1 unsat at sn2)

Question 14

3 main types of sphingolipids

Answer 14

ceramides, sphingomyelins, glycosphingolipids

Question 15

what are sphingolipids synthesized from?

Answer 15

palmitic acid and serine

Question 16

where do ceramides exist in high concentration?

Answer 16

skin stratum corneum

Question 17

where do sphingomyelins exist in high concentrations?

Answer 17

mammalian cell membranes

Question 18

Glycosphingolipid fxns

Answer 18

interact with proteins and other membranes, organize micro-domains, regulate receptors, signal transduction

Question 19

Gangliosides

Answer 19

sialic acid containing glycosphingolipids found mostly in nervous system

Question 20

Gangliosides play roles in: (7)

Answer 20

dev of neurons, neurotransmission, cell differentation, cel signaling, neuroprotection, nerve regeneration, apoptosis

Question 21

major class of membrane sterols?

Answer 21

cholesterol (4 joined rings)

Question 22

fats are ______ while phospholipids are __________

Answer 22

hydrophobic

amphipathic

Question 23

______ are the most favorable forms of lipid bilayers

Answer 23

liposomes

Question 24

Extracellular space is rich in ______ (3)

Answer 24

PC, SM, glycolipids

Question 25

cytosol side is rich in _______

Answer 25

PE, PS, PI

Question 26

Unique phospholipid that is almost exclusive to inner MM and plays a role in what?

Answer 26

cardiolipin, respiration and energy conversion

Question 27

fluid mosaic model

Answer 27

membrane is a mosaic of protein molecules bobbing in a fluid bilayer of phospholipids; allows for free diffusion of lipids, lateral diffusion of proteins, and membrane fusion

Question 28

3 factors that influence membrane fluidity

Answer 28

fatty acid composition (length/saturation), temperature, cholesterol content (buffer)

Question 29

_____ is a phospholipid that fxns in signal transduction

Answer 29

PIP2 (causes release of IP3, DG)

Question 30

a polypeptide chain usually crosses the bilayer as ________-

Answer 30

alpha helix

Question 31

cell surface is coated with _______

Answer 31

carbohydrate

Question 32

around _____ euk genome encodes integral membrane proteins

Answer 32

30%

Question 33

6 major membrane protein fxns

Answer 33

``` transport enzymatic activity signal transduction cell-cell recognition intercellular joining attachment to cytoskeleton and ECM ```

Question 34

______ can cross membranes rapidly

Answer 34

small non-polar/hydrophobic molecules and gases

Question 35

Active transport

Answer 35

requires ATP bc moves from low to high concentration

Question 36

Passive transport

Answer 36

doesnt require energy bc moves from high to low concentration

Question 37

Facilitated diffusion consists of 2 classes of proteins:

Answer 37

channel and carrier proteins

Question 38

B-barrel proteins are usually found in the ____

Answer 38

mitochondria

Question 39

plasma membranes are usually _____ and are strengthened by ____

Answer 39

fragile, framework of proteins

Question 40

A ________ forms the cell cortex bw human RBC

Answer 40

spectrin

Question 41

Lateral mobility can be restricted by:

Answer 41

being tethered to cell cortex, ECM, and proteins on surface of another cell, and by barriers of diffusion on polarized cell

Question 42

3 roles of membrane carbohydrates

Answer 42

protect cell from damage absorb water play roles in cell-cell recognition

Question 43

cell-surface carbohydrate recognition on neutrophils mediates ____

Answer 43

migration in infection

Question 44

flippase

Answer 44

transfer some of the phospholipids to the other leaflet

Question 45

transport vesicles

Answer 45

bud off from the golgi membrane and fuse with plasma membrane to deliver new molecules

Question 46

which has more proteins than sugar? glycoproteins or proteoglycans

Answer 46

glycoproteins