quiz 1.2 lipids-membrane Flashcards
thickness ng membrane
6-10nm
the translocation of lipid molecules from one positon to another
assymetry
typical charge of the inside of the membrane
-60mV
the major membrane forming lipids
glycerophospholipids
sphingolipids
glycerophingolipids
cholesterol
most abundant lipid in membrane
glycerophospholipid/phosphoglyceride
the simplest glyceropphospholipid
phosphatidic acid
common glycerophospholipids in membrane
phosphatidylcholine
phosphatidylethanolamine
phosphatydilserine
phosphatidylinostiol
anong glycerophospholipids ung nsa lacholinebas
phosphatidylcholine
common sphingolipids in the membrane
ceramide
sphingosine
backbone ng sphinglipids
sphingsoine
the predominant sphingolipid in myelin sheath
sphingomyelin
structure ng ceramide
sphongosine na may fatty acid via amide bond
backbone ng glycosphingolipids
ceramide
glycosphingolipids are either
cerebroside or ganglioside
simplest glycosphinglipid
cerebroside
glucocerebro or galactocerebro which is found in non-neural tissue
glucocerebroside
this glycosphingolipid contains one or more N-acetylneuraminic acid or sialic acid units
ganglioside
ganglioside GM1 serves as a receptor that binds
cholera toxin, influenza virus, E. coli enterotoxin, etc
ganglioside GM2 accumulates in the tissues of infants with
Tay-Sach’s dse due to a deficiency in n.acetylneuraminic acidlp
most commons sterol in plasma membrane
cholesterol
function ng cholesterol sa membrane
immobilize of the first few hydrocarbons of the phospholipid para less deformable
prevents crystallization of the hydrocarbons
4 types of lipid anchoring motifs
amide-linked myristol
thioester-linked fatty acyl
hioester-linked prenyl
glycosyl phosphatidylinositol (GPI)
where are carb contents of membrane found?
outside
spherical structures that form bcoz of the amphipathic character of lipids
hydrophilic heads outside hydrophobic tails inside
micelles
concentration of lipid required for micelle formation
critical micelle formation
spherical vessel formed when a lipid bilayer closes in on itself to form separating the external environment from internal aqueous compartment
liposome
mobility of membrane lipids
rapid lateral diffusion
rapid rotational diffusion
very slow transverse flipflop exchange
rapid flexing of hydrocarbons chains
who proposed Fluid Mosaic model
Jonathan Singer and Garth Nicholson 1972
two roles of the lipid bilayer accdg to fluid mosaic model
sovent for intergral membrane proteins and permeability membrane
specialized structures in the membrane
lipid rafts
caveolae
tight junctions
microdomains composed of lipids and proteins in both the outer and inner layer, in cellular membranes, destined to itneract with plasma membrane
lipid raft
where are lipid rafts assembled in mammalians
golgi complex
ano nsa inner at outer leaflets ng lipid rafts
outer: glycosphingolipids and cholesterol
inner: phospholipids and cholesterol
resistant to detergent solubilization
lipid rafts
flask-shaped indentations of the cytosolic side of the cell formed from the lipid rafts
caveolae
ano ung nsa caveolae na responsible daw sa formation nito
caveolin-1
found on membrane surfaces that work to prevent the diffusion of macromolecules between cells
tight junctions
what influences the fluidity of the membrane
lipid composition and temp
shorter chain length _____ membrane fluidty and _____ transition temp
increases; reduces
the temp at which the membrane “melts” to adopt a semifluid crystalline state
transition temp
what happens at transition temp
membrane melts to adopt semifluid crystalline state
increasing degrees of unsaturation _______ membrane fluidity
increases
ethanolamine or choline which increases the Tm greater
ethanolamine
_____ does not change but broadens the fluidity range considerably
cholesterol
at normal body temp, the bilayer kis at ____
fluid state
_____ temp decreases fluidity
lower
properties of the emmbrane
fluidity
selective permeability
self-sealing capability
asymmetry
measure of the ability of the molecule to diffuse across a permeability membrane
permeability coefficient
preferentially found outside the membrane in rbcs
sphingomyelin and phosphatidylcholine
bakit namaintain ung assymetry ng membrane or bakit walang same shit on opposite sides
proteins do not rotate from oen side to thee other
results in the difference of fluidity between the two leaflets and a difference in cahrged groups
assymetry
examples of lipid transpoters that maintain the asymmetry in the membrane
aminophospholipid translocase/flippases
floppase
phospholipid scramblase
catalyzes the transport of phosphatidylserine and ethnaolamine from outside to inside, responsible for maintaining low conc. of these in the ECF
aminophospholipid translocase/flippase
an outward directed transport that is nonspecific for phospholipids
floppase
facilitates the bidirectional mixing of phospholipids between the two leaflets
phsopholipid scramblase
elongated and is the primary component of the cytroskleton underlying the rbc membrane
spectrin
accounts for the biconcavity and flexiblity fo the cell
spectrin
resistant to shear ang rbc kasi si spectrin nagbbind kina
ankyrin and band 4.1
peripheral membrane protein sa rbc membrane na globular and filamentous
actin
large globular polypeptide mainly responsible for attaching the spectrin cytoskeleton to the RBC membranee and to the anion channel
ankyrin
binds both spectrin and actin
band 4.1
two major intergral proteins in rbc membrane
glycophorin band 3 (anion channel)
literal meanig of glycophorin
to carry sugar
single pass transmembrane intergral protein composed of three regions
glycophorin
most abundant erythrocyte membrane protein
band 3
a multipass transmembrane protein composed of two identical subunits
band 3
band 3 is a tubular channel that mediates the exhcange of
HCO3 for Cl-
beta barrel channel examples
aquaporin
aquaglyceroporin
channel selcetive for water
aquaporin
channel selective for water and small neutral organic molecule
aquaglyceroporin
an ionophore that creates a pore in the membrane, that permits passage of protons and alkali cations but not anions
gramicidin A
facilitates the transport of glucose in both directions demonstrating reversibility of the system
RBC glucose transporter (glut-1)
has hydrophobic outer and interior are well suited to chelate ions
valinomycin
characterized by less fluid on the outer surface and more in the hydrophobic core
hypercholesterolemia
in alcoholic cirrhosis there is _________
dec. fluidity
also reduces fluidity of the membrane
ethanol intoxication
abetalipoproteinemia
assoc. with spheroidal RBCs and clinically, hemolytic anemia
HS
RBCs appear elongated/elliptical, but confers resistance to malaria when hetero
HE
abnormalities in membrane during HS
spectrin def
combined spec and anky def
band 3 def
protein 4.2 def
fatal autosomal recessive condition inherited among caucasians
cystic fibrosis
gene product efective in cystic fibrosis
CFTR cystic fibrosus transmembrane conductance regulator
principal anifestation in cystic fibrosis
pulmonary obstructiokn
result of a decrease in the transport of neutral amino acids in the epith cells in the int. tract and renal tubules
hartnup dse
classif of lipids
simple
compound
derived
example of simple lipids
TAG
waxes
example of compound lipids
phospholipids
sphingolipids
glycolipids
examples of phospholipids
lecithin
cephalin
plasmalogen
lipositol
phospholipid found in brain, egg yolk, etc. used as emulsifier in food industry
lecithin
phospholipid that occurs predominantly in the nervous tissues
cephalin
phospholipid found in heart, brain, muscle
plasmalogen
phospholipid foun din kidney brain heart plant tissues
lipositol
sphingolipid found in brain and nervous shit and rbcs
sphingosine
examples of glycolipids
cerebroside
ganglioside
sulfolipid
proteolipidp
glycolipid na nasa myelin sheaths ng nerves brain etc. ydrolysis yields fatty acids, sphingosine, galactose/glucose
cerebroside
ganglioside is notably seen in
spleen
struture of ganglioside
ceramide na may hexose, fatty acid, neuraminic acid, sphingosine
examples of derived lipids
terpenoid and steroids
sterols
fatty acid
large group of compounds made up of repeating isoprene units
terpenes
examples of sterols
choelsterol ergosterol 7-dehydrocholesterol androgens and estrogens adrenal corticosteroids
cis configuration of fatty acids are bent at
120degrees
naturally occuring fatty acids are in cis or trans
cis
states that double bonds are interrupted by a methylene group, which forms a pentadiene structure
nonconjugated double bond system
liquid ang fatty acid kapag
1-8 atoms lng
increase in chain length _____ in boiling point and melting point
increase
melting point ____ with increasing unsaturation
decrease
solubility ____ with inc. length
decreases
saturated fatty acids include
laurate 12 myristate 14 palmitate 16 stearate 18 arachidate 20 behenate 22 lignocerate 24
rxn involving TAG
hydrolysis (saponification, enzymatic, transesterification)
hydrogenation
nonabsorbable cooking oil made by combining veg oil and sucrose
olestra
backbone ng phosphoglycerides
glycerol
3 principal classes of plasmalogens
phosphatidal serine choline and ethnaolamines
constituent of mitochondrial membranes`
cardiolipin
saan sa sphingosine nagaattach ang polar heads
C1
saan sa sphingosine nagaattach ang fatty acids
C2
structure ng ceramide
sphingosine na may fatty acid
sa sphingomyelin, ano nakaattach sa ceramided
phosphatidylcholine
