Biomembranes & Membrane Transport Flashcards
1
Q
In a cell membrane, glycoconjugates are oriented toward the ______
A
extracellular space
2
Q
Penguins cell membranes would likely contain a high content of _____
A
unsaturated phospholipids
3
Q
which FA has less kinks?
A
saturated
4
Q
what do kinks do to the membrane?
A
makes it more fluid, less waxy
5
Q
which side of the membrane is oxidizing?
A
extracellular
6
Q
which side of the membrane is reducing?
A
intracellular
7
Q
which side of the membrane has low phosphatidyl serine?
A
extracellular
8
Q
which side of the membrane has high phosphatidyl serine?
A
intracellular
9
Q
which side of the membrane has a high [Na]?
A
extracellular
10
Q
which side of the membrane has a low [Na]?
A
intracellular
11
Q
which side of the membrane has a low [K]?
A
extracellular
12
Q
which side of the membrane has a high [K]?
A
intracellular
13
Q
which side of the membrane has a high [Ca]?
A
extracellular
14
Q
which side of the membrane has a low [Ca]?
A
intracellular
15
Q
which side of the membrane has high phosphatidylcholine?
A
extracellular
16
Q
which side of the membrane has low phophatidylcholine?
A
intracellular
17
Q
which side of the membrane has high phosphatidylinositol 4,5-bisphosphate (PIP2)?
A
intracellular
18
Q
what maintains the membrane asymmetry?
A
flipases and flopases
19
Q
what makes up a phosphatidic acid?
A
DAG + phosphate on C3
20
Q
cephalin
A
phosphatidylethanolamine (PE)
21
Q
lecithin
A
phosphatidylcholine (PC)
22
Q
what is the charge on phosphatidylethanolamine?
A
+
23
Q
what is the charge on phosphatidylcholine?
A
+
24
Q
what is the charge on phosphatidylserine?
A
net = 0 (zwitterion)
25
what makes up a cardiolipin?
2 phosphatidic acids esterified to glycerol through their phosphate head groups
26
cardiolipin location
inner mitochondrial membrane
27
what does cardiolipin do?
stabilizes ETC complexes
28
what makes up a plasmalogen?
FA at C1 replaced by unsaturated alkyl chain with ether link
29
plasmalogen location
CNS
30
what makes up platelet activating factor?
- SATURATED alkyl group via ether link to glycerol C1
| - acetyl group C2
31
what does plasmalogen do?
triggers thrombotic and inflammatory events
32
what is the backbone of sphingophospholipids?
amino alcohol spingosine instead of glycerol
33
what makes up spingophospholipids?
FA + sphingosine (amide link) + R group
34
sphingophospholipid + H
ceramide
35
sphingophospholipid + phosphocholine
sphingomyelin
36
sphingophospholipid + sugar
glycosphingolipid
37
which sphingophospholipid is a good 2nd messenger?
ceramide
38
why is mental retardation common in lysosomal storage diseases?
- lysosomal enzymes important for catabolizing sphingolipids
| - sphingomyelin = myelin not there to protect axons = mental retardation
39
Lysosomal Storage Diseases
- Tay-Sachs disease
- Fabry's disease
- Metachromatic leukodystrophy
- Krabbe's disease
- Gaucher's disease
- Niemann-Pick disease
- Farber's disease
40
what causes the crumpled tissue paper appearance of the cytoplasm of Gaucher cells (macrophages)?
enlarged, elongated lysosomes filled with glucocerebroside
41
what is phosphatidylinositol (PI) made of?
inositol + DAG at C3
42
phosphorylation of PI results in what?
polyphosphinositides (phosphatidylinositol 4,5-bisphosphate)
43
what is the pathway to get inositol phosphates (IPs)?
1-cell signaling
2-phospholipase activation (cleavage at phosphate head group)
3-release of 2nd messenger (IP)
44
where is phosphatidylinositol 4,5-bisphosphate cleaved by phospholipase C to form 1,4,5-IP3?
phosphate head group on C3
45
what does IP3 release?
Ca++ from internal stores in ER and sarcoplasmic reticulum
46
which enzyme cleaves phosphatidylinositol 4,5-bisphosphate?
phospholipase C
47
what can also act as an anchor to membranes using sugar?
glycosylphosphoinositol
48
which side of the glycosylphosphoinositol is inserted into the lipid core of the cell membrane?
the lipophilic side chain
49
what are tocopherols (Vitamin E) used for?
- Lipophilic component of cell membrane
- Inhibits the chain reaction of lipid peroxidation
- Generates free radical which is recovered by Vitamin C
50
what is necessary for pregnancy otherwise the fetus will get absorbed too quickly?
Vitamin E
51
3 types of membrane proteins
- integral proteins (intrinsic)
- peripheral proteins (extrinsic)
- transmembrane proteins
52
which membrane proteins cannot be separated easily with detergents?
integral
53
which proteins are loosely associated?
peripheral
54
which subtype of transmembrane protein has:
- single transmembrane helix
- COO on inside
type 1
55
which subtype of transmembrane protein has:
- single transmembrane helix
- COO on outside
type 2
56
which subtype of transmembrane protein has:
- single protein
- multiple transmembrane helices
type 3
57
which subtype of transmembrane protein has:
- multiple proteins
- single transmembrane helix
type 4
58
which subtype of transmembrane protein has:
| -lipid-linked proteins
type 5
59
which subtype of transmembrane protein has:
- transmembrane domains
- lipid-linked domains
type 6
60
actin based
microfilaments
61
tubular based
microtubules
62
rigid rod with a (+) growing end and a (-) shrinking end
microtubules
63
what makes up a strand of F actin?
G-actin monomers
64
main tracks for longer distance transport
microtubules
65
movement from - to +
anterograde
66
movement from + to -
retrograde
67
anterograde motors
kinesin
68
retrograde motors
dynein
69
actin filament location
microvilli of intestinal epithelium
70
actin stress fibers function
keep cells in rigid conformation when adhering to a surface
71
what helps cells crawl around?
- Filopodia (pointed)
- Lamellipodia (flattened)
- Pseudopodia (false foot)
- Fagocytosis
- Ambeoid movement
72
what filament makes up a cytokinetic cytokinesis?
actin filaments
73
which side of the membrane has high GSH and GSSG?
intracellular
74
which side of the membrane has high NADPH
intracellular
75
which side of the cell has mostly disulfide (S-S) bonds?
extracellular
76
what type of transporter is erythrocyte glucose transporter?
facilitated diffusion
77
does simple diffusion need a concentration gradient?
no
78
does ion channel need a concentration gradient?
yes
79
which transporter uses energy?
active transport
80
does facilitated diffusion use energy?
no
81
which transporters move from HIGH to LOW?
- diffusion
- facilitated diffusion
- osmosis
- secondary active transport
82
which transporter moves from LOW to HIGH?
primary active transport
83
which molecules diffuse across phospholipid membranes?
- small
- hydrophobic
(O2, CO2, N2)
84
how many molecules does facilitated diffusion move?
1 (uses a conformational change)
85
GLUT 1 location
tissues
86
GLUT 2 location
liver and pancreatic beta cells
87
GLUT 3 location
tissues
88
GLUT 4 location
muscle and fat cells
89
GLUT 5 location
small intestine
90
GLUT 1 Km
low
91
GLUT 4 Km
high
92
which GLUT is for fructose?
GLUT 5
93
osmosis
movement of solvent through a semipermeable membrane down its concentration gradient
94
which active transporter directly uses ATP?
primary active transport (Na/K pump)
95
which active transporter indirectly uses ATP?
secondary active transport (Na/Ca++ pump)
96
which active transport has one solute moving with its gradient and the other moving against its gradient?
secondary active transport
97
example of symporter
SGLT 1
98
SGLT 1 location
Epithelial Cells:
- small intestines
- heart
- brain
- proximal tubules of kidneys
99
SGLT 1 exchange ions
1 Glucose or Galactose for 2 Na+
100
how are amino acids transported?
symported with Na+
101
damaged amino acid symporter causes what?
increased concentration of amino acids
102
3 types of endocytosis
- phagocytosis
- pinocytosis
- receptor-mediated endocytosis
103
which type of endocytosis takes in fluids into the cell by invagination of the cell membrane?
pinocytosis
