Cell Membrane - Exam 2 Flashcards
1
Q
function: separate antiparallel processes such as
A
FA synthesis in cytosol & FA oxidation in mitochondria
2
Q
function: separate similar reactions for different purposes such as
A
FA oxidation: in mitochondria for energy & in peroxisomes for heat
3
Q
function: coordinate reactions in same pathway for energy efficiency such as
A
TCA & ETC
4
Q
width of membrane
A
5-10nm (thin)
5
Q
membrane is impermeable to
A
H2O soluble molecules
6
Q
components
A
lipids, proteins, carbs, H2O, divalent cations, cholestrin (eukaryotes)
7
Q
% protein _____ than % lipid in all cases except……
A
higher; liver cells of mice
8
Q
inner mitochondrial membrane % compositions
A
24% lipid, 76% protein, 1-2% carbs
9
Q
gram positive bacteria % compositions
A
25% lipid, 75% protein, 10% carbs
10
Q
3 main lipids
A
phospho, sphingo, cholesterol
11
Q
phospholipid composition
A
polar hydrophilic head, nonpolar hydrophobic tails
12
Q
cis-double bond means
A
kink = unsaturated
13
Q
polar head composition
A
choline, phosphate, glycerol
14
Q
3 types of phosphoglycerides
A
phosphatidyl-ethanolamine, -choline, -serine (neg. charge)
15
Q
sphingolipid example
A
sphingomyelin
16
Q
lipid micelle shape
A
cone-shaped
17
Q
lipid bilayer shape
A
cylinder-shaped, energy efficient when curled into ball
18
Q
inner monolayer mostly comprised of
A
phosphatidylethanalomine
19
Q
outer monolayer mostly comprised of
A
phosphatidylcholine & sphingomyelin
20
Q
flex movement
A
tails turn back & forth
21
Q
transversal diffusion movement
A
inner & outer switch
22
Q
lateral diffusion movement
A
2 on same side switch
23
Q
phase transition
A
liquid -> gel, short chain/double bond decrease this & temperature
24
Q
fluidity depends on
A
lipid composition, cholesterine content, temperature
25
decrease temperature means _____ movement; increase temperature means _____ movement
less; more
26
what kind of FA has less space between tails
saturated
27
what kind of FA has more space between tails
unsaturated because of kinks
28
cholesterin effect on fluidity
inserts in between tails, increases fluidity
29
fluidity measured by
fluorescence microscopy & FRAP (diffusion)
30
ECM function
"extracellular matrix"; direct mechanical stress/tension/compression
31
glycosaminoglycans found in
"bristle brush", cartilage, hyaluronan
32
fibrous proteins found in
collagen (skin & bone), type 4, fibrillar
33
noncollagen fibrous proteins found in
glycoproteins (laminin, nidogen, fibronectin)
34
collagen characteristics
glycosylated, proline, glycerine
35
type I collagen
bone, skin, tendons, ligaments, cornea, internal organs (majority)
36
type II collagen
skin, blood vessels, internal organs
37
elastin characteristics & function
covalent bonds (cross linkage), hydrophobic, not glycosylated, proline, glycerine, elasticity like "rubber band" for extension/contraction
38
elastin found in
skin, blood vessels (aorta), lungs
39
fibronectin function & shape
organizes ECM, cell attachment; Y shape (connected by disulfide bridge)
40
laminin function & shape
organizes sheets of basal lamina, polypeptide chains linked by disulfide bonds, asymmetric
41
integrins function
transmembrane cell adhesion, link cytoskeleton with ECM
42
microtubules characteristics
"protofilaments", 24nm, centrosome (MTOC), tubulin, alpha & beta
43
alpha microtubule subunit characteristics
negative end, GTP trapped
44
beta microtubule subunit characteristics
positive end, GTP (growth), GDP (shrink)
45
MAP function
microtubule associated proteins, "walk", move pigment (melanosomes)
46
kinesin moves towards
positive end
47
dynein moved toward
negative end
48
taxol/paclitaxel
drug from Yew tree for chemo because blocks microtubules
49
flagella function
move in liquid like sperm
50
cilia function
move fluid above a cell like mucous
51
actin characteristics
"microfilament", 7nm, F-actin (filamentous)
52
ATP effect on actin
increase affinity for neighboring subunit, stable
53
ADP effect on actin
easily dissociate
54
bundle forming crosslinker composed of
fascin
55
gel forming crosslinker composed of
filamin
56
actin movement (general)
polymerize (grow), depolymerize (shrink)
57
actin movement (specific)
stress fiber (contractile bundle), cortex (gel-like network), & filopodium (tight parallel bundle)
58
myosin (contraction) not bound without
Ca2+
59
intermediary filaments function
8-12nm, strengthen cells & epithelia, no movement,
60
type I & II intermediary filament
acid & basic keratin, found in epithelial cells
61
type III intermediary filaments
vimentin (fibroblasts, endo cells, leukocytes)
desmin (muscle, glial fibrils)
peripherin (nerve cells)
62
type IV intermediary filament
neurofilament H, M, L
| filensin/phakinin (lens of eyes)
63
type V intermediary filament
lamin (nuclear membrane)
64
transport proteins what % of all membrane proteins
15-30
65
common extracellular molecules
Na+, Mg2+, Ca2+, Cl-
66
common intracellular molecules
K+, H+
67
4 examples of hydrophobic (permeable) molecules
O2, CO2, N2, steroid hormones
68
3 examples of small uncharged polar (carrier) molecules
H2O, urea, glycerol
69
2 examples of large uncharged polar (carrier) molecules
glucose, sucrose
70
7 examples of ions (channels)
H, Na, HCO3, K, Ca, Cl, Mg
71
membrane "resting" potential
unstimulated, difference in electrical charge, result of active transport & passive diffusion
72
Na K ATPase function
pumps Na out, K in
K diffuses out through channels
negative ions stay inside
interior: -70 mV -> -90 mV
73
no membrane potential means
only a chemical gradient, not efficient
74
negative membrane potential means
efficient = real life
75
positive membrane potential means
movement of negative charged ions impaired, not efficient
76
SGLT function & placement in membrane
Na/Glucose cotransporter, apical
77
GLUT placement in membrane
basolateral
78
NCX function
Na/Calcium exchanger, alternative splice sites (isoforms)
79
hydropaty analysis shows
more hydrophobic = higher probability of seeing transmembrane protein domain
80
transporter characteristics
bind specific substrate, conformational changes
81
channels function
pores for specific solutes
82
ion channel characteristics
gate -> selectivity filter (dehydrated), Na
| vestibule (ions = hydrated)
83
voltage-gated channels examples
Na+, CNS (neurons)
84
ligand-gated extracellular channel example
nicotinergic receptor acetylcholine (muscle)
85
ligand-gated intracellular channel example
Ca2+ (second messenger)
86
mechanically gated channel example
"mechanosensitive", K+ channels, inner ear/hair
87
passive diffusion characteristics
net flow is down [gradient], no membrane proteins needed, dissolve in, move through, dissolve out
88
facilitated diffusion characteristics
no external energy source, direction determined by [gradient] & electrical potential, don't dissolve because mediated by proteins, pass polar molecules
89
diffusion & channel mediated transport rates (graph)
directly proportional to [solute] (straight line)
90
carrier mediated transport saturable (graph)
upward curve, never reaches max
91
active transport uses
energy
92
uniport function
1 molecule passively transported
93
example of a uniport
GLUT
94
symport function
2 molecules transported in same direction
95
example of a symport
Na+
96
antiporter function
transport 2nd molecule in opposite direction
97
example of an antiport
Na K ATPase
98
primary active transport driven by
ATP
99
primary active transport: P type
phosphorylate themselves
100
primary active transport: ABC
ATP binding cassette, 2 sites, majority
101
primary active transport: F/V type
ATPases & ATP synthases
102
secondary active transport driven by
gradient generated in primary active transport
103
secondary active transport: symport
SGLT (1 glucose + 2 Na+ in)
104
secondary active transport: antiport
NCX & NHE
105
NHE function
sodium/proton exchanger
106
tertiary active transport driven by
gradient generated by secondary active transport
107
tertiary active transporter example
proton/peptide symporter (H+ gradient from secondary active transport)
108
proton/peptide symporter found
kidney, SI because efficient
109
aquaporins function & place found
specific H2O channels, use ADH; kidney
110
ADH use in urine formation
ADH stimulated by osmoreceptors (hypothalamus) when dehydrated, stimulate H2O reaborption
