Chapter 12 Flashcards
(105 cards)
1
Q
HIV leaves from an infected cell by
A
budding off the membrane to form a vesicle
2
Q
vesicle uses
A
lipid bilayer membrane as the cells
3
Q
Membranes form ____ between compartments
A
closed boundaries
4
Q
Membranes consist mostly of
A
lipids and proteins
5
Q
Lipids have ______ to form bilayers
A
both hydrophilic and hydrophobic moieties
6
Q
Proteins provide
A
specific functions w/in the membranes (pumps, channels, receptors, etc.)
7
Q
Membranes associate due to
A
non-covalent forces (hydrophobic effect)
8
Q
Membranes are
A
asymmetric
9
Q
asymmetric
A
their internal and external faces are different
10
Q
Fluidity
A
lipids (and proteins) diffuse laterally w/in the membrane, but do not flip
11
Q
Membranes polarization
A
inside is negative to promote regulated transport
12
Q
Fatty acids
A
oxidized hydrocarbons
13
Q
Fatty acids given systematic names based on
A
their saturated hydrocarbon, as well as common names
14
Q
Palmitic acid numbers
A
be 16:0 because it has sixteen carbons and no double bonds
15
Q
Palmitic acid
A
a saturated fatty acid, that is what we call FA with no double bonds.
16
Q
Oleic Acid
A
mono-unsaturated, it has one double bon
17
Q
18:1∆9
A
an Oleic Acid -> Eighteen carbons and one double bond - 9 carbons
18
Q
Oleic Acid was named after
A
olive oil
19
Q
palmitic acid named after
A
palm oil
20
Q
omega end
A
The last CH3
21
Q
Double bonds can either be designated as
A
delta x (x carbons from carboxy end) or omega -x
22
Q
Palmitate
A
n-Hexadecanoate
23
Q
Stearate
A
n-Octadecanoate
24
Q
palmitoleate
A
cis-delta 9-hexdecenoate
omega-7
25
Oleate
cis-delta 9- octadecenoate
omega-9
26
Lineleate
cis,cis-delta 9-octadecadienoate
omega-6
27
linolenate
all-cis-delta 9,12, 15 - octadecatrienoate
omega-3
28
arachidonate
all-cis delta 5, 8, 11, 14 - Eicosatetraenoate
omega-6
29
Effects on fluidity:
-Short chain length has lower melting point than longer fatty acids.
-Unsaturations greatly reduce melting points (increase fluidity)
30
Why do unsaturations greatly reduce melting point
A crystalline solid is aided by uniform latice structure which is disrupted by unsaturations
31
Humans are unable to synthesize
omega-3’s and omega-6’s, but can be get with linoleic
(Linoleic (w-6) and linolenic (w-3) )
32
linoleic is important in the brain
especially important in childhood development
33
Membrane lipids
-Phospholipids
-Glycolipids
-Cholesterol
34
Phospholipids are composed of:
1. Fatty acids
2. A platform to link them (glycerol or sphingosine)
3. Phosphate
4. Alcohol
35
The alcohol and phosphate in a phosphatidyl lipid are called
the “polar head group” to aid its solubility in water
36
phosphatidyl is overall
amphipathic
37
amphipathic
having both hydrophilic and hydrophobic parts
38
Phospholipids derived from glycerol are called
phosphoglycerides
39
the simplest phosphoglyceride
phosphatidate
40
phosphatidate do not have
“alcohol” attached to the phosphate
41
chiral carbon
carbon atoms that are attached to four different substituents
42
typical eukaryotic phosphatidyl lipid head groups
note N+
43
eukaryotic phospholipids
serine, ethanolamine, choline
44
typical prokaryotic phosphatidyl lipid head groups
glycerol and inositol
45
important for eukaryotic signalling
Phosphatidyl inositol
46
phosphatidyl head groups are joined by
esterification to the phosphate
47
Phosphatidyl inositol have
extra phosphates on the ring
48
phosphatidyl choline is often known by its trivial name, “lecithin”, which is an
amphipathic emulsifier.
49
An important bacterial lipid is
phosphatidylglycerol
50
Cardiolipin is based on phosphatidylglycerol but it has
TWO phosphatidates in its structure
51
alkylacyl-
refers to one acyl and one alkyl ether bonded to glycerol
52
Sphingomyelin
a phospholipid with sphingos backbone
53
Sphingolipids are found in
eukaryotic cells (mostly animals, some plants and yeast)
54
If your triglyceride has a positively charged residue (N+) then it most likely comes from a
eukaryote
55
Glycolipids are derived from
sphingosine but are not phospholipids
56
Glycolipids have
a glycosidic linkage (to carbon one) of glucose or galactose
57
Sphingosine plus one fatty acid
ceramide
58
Gangliosides have
branched chains of up to 7 sugars
59
Cholesterol
found only in animal nucleus in order for membranes to be flexible
60
Cholesterol effect
lowers the melting point and increases the fluidity of eukaryotic membranes (also used to digest lipids)
61
Archael phospholipids are based on
ether linkage
62
Archaea
single celled prokaryotes that like to live in extreme environments
63
Archael membranes
do not use fatty acid esters, but alkane ethers
64
Archael membranes
can either be bilayers or monolayers
65
The ether bonds to glycerol are stronger in
hot or acidic environments than esters would be
66
ether
R-O-R'
67
In the membrane, the polar head groups are
hydrophilic
68
In the membrane, the acyl chains are
hydrophobic
69
leaflets
One half of a lipid bilayer (two hydrophobic tails)
70
lipid bilayer membrane is like
soap bubble, no strength
71
Soaps
salts of fatty acid that solublize oil, cells, and dirt in micells
72
hard water
difficulty washing as solubility of soaps is low
73
hard water solution
“water softeners” (like detergents) that remove the Mg2+ and Ca2+ from the water
74
What can pass through a cell membrane
Uncharged molecules with some hydrophobicity (like water, but not sodium)
75
fluid mosaic model
describes the plasma membrane as a fluid combination of phospholipids, cholesterol, and proteins
76
Integral membrane proteins
like pumps and channels, and receptors
77
Peripheral proteins
can be “tethered” to the membrane, or attach to a integral protein or simply be attracted to the membrane surface
78
peripheral proteins can be removed by
high salt
79
integral proteins are removed by
detergents to disrupt the membrane andkeep the protein soluble in an aqueous solvent
80
Bacteriorhodopsin
a type of 7TM receptor
81
“7TM” receptor
a seven-helix trans-membrane receptor that spans the entire width and loops extent in and out of cell
82
Most common type of integral membrane protein
7TM” receptor
83
channel protein porin
makes a “hole” or “pore” in the outer membrane of gram negative bacteria – letting food in and waste out
84
channel protein porin is made of
anti-parallel beta strands that form sheets that make a hollow cylinder or “barrel” shape.
85
beta barrel
porin
86
arachidonic starting material for
prostaglandin synthesis
87
Prostaglandin H2 (internal membrane)
promotes inflammation (pain) and gastric acid secretion
88
Membrane anchors
Protein with internal cysteine is conjugated to a fatty acid
89
Membrane anchors covalently attached by
cysteine’s sulfhydryl or the C-terminus
90
Fluid-Mosiac Model
used to measure diffusion of proteins in a membrane by bleaching fluorescent labeled proteins with a laser to form a white dot, but over time unbleached proteins diffuse into the spot (recover)
91
The diffusion rate of lipids indicates
they can traverse an E. coli cell in 1 sec
92
transmembrane proteins are immobile due to
them anchoring the cytoskeleton
93
Lateral diffusion
rapid
94
Tranverse diffusion (flip flop)
very slow
95
Fatty acid composition determines
membrane fluidity
96
The melting temperature of a lipid can be taken as
a measure of viscosity
97
The longer the fatty acid
the higher the melting point
98
Adding a ONE double bond will ______ the melting point
dramatically reduce
99
Membrane lipids can not be completely _____ to function properly
"solid" there needs to be fluidity
100
Human diets need to be
unsaturated (add double bond) in order fatty acid not to form solid membrane lipids
101
Naturally occurring un-saturated fatty acids have
"cis" double bonds and are bent, causing them to be harder to stack (lower melting temps)
102
A triglyceride that is liquid at room temperature
oil
103
triglyceride that is solid at room temperature
a fat
104
Trans-fat
raises melting temp and increases shelf life of veggie oil
105
Today in our food, Trans fats have
lowered from the original
