IMS 7 - cell membrane and signalling
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- Created by: Ettie Conway
- Created on: 07-05-24 19:58
which is not a lipid found in the cell membrane?
terpenes
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which statement is correct about glycerophospholipids?
sn-1 fatty acid usually saturated sn-2 fatty acid usually mono or polyunsaturated
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which is not an anionic phospholipid?
PC
3 of 91
anionic phospholipids...
have a negative charge
4 of 91
zwitterionic phospholipids.....
have zero charge
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PS and PE ...
contain reactive
amines that can participate in
hydrogen bonds
amines that can participate in
hydrogen bonds
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PI, PC and CL
affect packing due to their bulkiness
7 of 91
organelle specific lipids e.g. PG and cardilipins
are only found in mitochondria
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which is the most common sphingolipid? (it has a phosphocholine headgroup)
sphingomyelin
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the amide group in sphingolipids has the ability to do what?
form hydrogen bonds
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what is ganglioside GM1 an example of?
glycosphingolipid
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sterols have a
hydroxyl group and a hydrocarbon chain
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most common type of sterol found in humans
cholesterol
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what in animal cells translocate to the extracellular monolayer when cells undergo cell death or apoptosis signalling for digestion?
phosphatidylserine
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where are glycolipids orientated towards?
exterior of the cell
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where are second messengers in signalling pathways orientated towards?
interior of the cell
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hydrolysis of PI(4,5)P2 results in the formation of which secondary messenger(s)?
diacylglycerol (DAG) and inositol-1,4,5-
triphosphate (IP3)
triphosphate (IP3)
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rotational lipid movement
The spinning of a lipids around its axis. Does not alter its position but affects its interaction with neighboring molecules.
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transverse lipid movement
The exchange of molecular between leaflets. Lipids can move across a
bilayer membrane spontaneously by transverse diffusion or their translocation can be mediated by proteins (unidirectional or bidirectional).
bilayer membrane spontaneously by transverse diffusion or their translocation can be mediated by proteins (unidirectional or bidirectional).
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lateral lipid movement
Neighboring lipids exchange places. It allows lipids to change position within a bilayer leaflet
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P-type flippases
carry out inward movement of lipids
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ABC proteins
mediate outward movement of lipids.
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scramblase
perform non-specific Ca2+-dependent
randomization of lipids across the bilayer
randomization of lipids across the bilayer
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glycophorin A is a
integral protein
24 of 91
bacteriorhodopsin is a
integral protein
25 of 91
GLUTs membrane-spanning region is composed of what?
12 a helices
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what have varying degrees of anionic surfaces?
lipid binding domains
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peripheral membrane proteins are linked to lipids inserted in membranes via what?
covalent bond
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myristoyl groups are connected to what?
glycine residues
29 of 91
what kind of glycoprotein is this?
contains a carbohydrate attached to the oxygen atom in the side chain of serine or threonine. often short consisting of 2-5 sugars
contains a carbohydrate attached to the oxygen atom in the side chain of serine or threonine. often short consisting of 2-5 sugars
o-linked
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what kind of glycoprotein is this?
glycoproteins contain a carbohydrate attached to the amide nitrogen atom in the side chain of asparagine amino acid
glycoproteins contain a carbohydrate attached to the amide nitrogen atom in the side chain of asparagine amino acid
n-linked
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asparagine residues can accept what when the residue is part of an asn-x-ser or asn-x-thr sequence ?
oligosaccharide
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what sugar is in the O antigen?
no extra sugar
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what sugar is in A antigen?
N-acetyl-galactosamine
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what sugar is in B antigen?
galactose
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agnosia
difficulty recognising and naming objects
36 of 91
aphasia
language problems
37 of 91
apraxia
difficulties in complex tasks
38 of 91
Alzheimer's individuals have lots of plaques made up of what?
amyloid-beta peptide
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what disease is this?
Loss of cohesion between the plasma membrane and the
skeleton as a result of the defective anchoring of the skeletal
network to the membrane. Cell shape changes to spherocytes.
Loss of cohesion between the plasma membrane and the
skeleton as a result of the defective anchoring of the skeletal
network to the membrane. Cell shape changes to spherocytes.
hereditary spherocytosis
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what causes 60% of common HS leading to anaemia?
deficiency in ankyrin
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what causes 20% of common HS leading to anaemia?
deficiency in sceptrin
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what causes 15-20% of common HS leading to anaemia?
Band 3 deficiency
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which is correct about aquaporins?
28 kDa protein, 6 trans-membrane a-helices, tetrameter with 4 pores for H2O
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autocrine signalling
a cell targets itself
45 of 91
endocrine signalling
a cell targets a distant cell through the circulation
46 of 91
juxtracrine signalling
a cell targets a neighbouring cell via direct contact (ligand/receptor or GAP junctions)
47 of 91
paracrine signalling
paracrine: a cell targets a neighbouring cell
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autocrine signalling negative feedback =
attenuation (self stimulation)
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autocrine signalling positive feedback =
amplification (trans-activation)
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paracrine
synaptic
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which is a secondary messenger
ions e.g ca 2+
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nicotine acetylcholine receptor (nAChR) is an example of what?
ligand gated ion channel
53 of 91
which statement is false about nAChR?
impermeable to K+
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which statement is false about GPCR?
faster than nAChR
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which statement is false about kinase-linked receptors?
2 transmembrane domains
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which statement is false about nuclear hormone receptors?
extracellular receptors
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steroid and thyroid hormones are examples of what?
nuclear receptors
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what % of cholesterol is from the diet? (not synthesized in liver)
25%
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which lipoprotein is this?
source: intestine
Transport of dietary fats (triglycerides,
cholesterol) from intestine to tissues
source: intestine
Transport of dietary fats (triglycerides,
cholesterol) from intestine to tissues
chylomicrons
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which lipoprotein is this?
source: liver
transport lipids made in the liver to peripheral tissues
source: liver
transport lipids made in the liver to peripheral tissues
VLDL
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which lipoprotein is this?
provide cholesterol for peripheral tissues, main cholesterol carrier
provide cholesterol for peripheral tissues, main cholesterol carrier
LDL
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which lipoprotein is this?
source: blood
transports cholesterol to liver from peripheral tissues
source: blood
transports cholesterol to liver from peripheral tissues
HDL
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which is correct?
lipid+ apolipoprotein = lipoprotein
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which apolipoprotein is this?
present in HDL, mediates efflux of cholesterol from
peripheral cells and influx to the liver
(subclasses: apo A-I, A-II, A-IV, A-V)
present in HDL, mediates efflux of cholesterol from
peripheral cells and influx to the liver
(subclasses: apo A-I, A-II, A-IV, A-V)
ApoA
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which apolipoprotein is this?
recognises apoB/E receptors, facilitates LDL uptake
(subclasses: apo B48, B100)
recognises apoB/E receptors, facilitates LDL uptake
(subclasses: apo B48, B100)
ApoB
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which apolipoprotein is this?
activator of lipoprotein lipase, transferred between
lipoproteins
activator of lipoprotein lipase, transferred between
lipoproteins
Apoc
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which apolipoprotein is this?
stabilises VLDL for cellular uptake, a ligand for the
apoB/E (LDL) receptor. Constituent of several classes of
lipoproteins
stabilises VLDL for cellular uptake, a ligand for the
apoB/E (LDL) receptor. Constituent of several classes of
lipoproteins
APoE
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apolipoprotein synthesis in the intestine is regulated by what?
dietary fat intake
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apoC-II regulates what?
lipoprotein lipase
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ApoA-I regulates what?
lecithin-cholesterol acyltransferase
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apoB100 targets
LDL receptors
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apoA-I targets
HDL receptors
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apo B is in?
LDL
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Apo A-I/II is in?
HDL
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which receptor binds apoB-100
or apoE?
or apoE?
LDL
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which receptor gene expression is regulated by intracellular cholesterol concentration?
LDL
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binding of what to a receptor stimulates endocytosis?
LDL
78 of 91
which lipoprotein?
released from the receptor in the endosome, and the receptor is recycled to the plasma membrane. Cholesterol is then released and used as required eg for
membrane synthesis, steroid hormone synthesis.
released from the receptor in the endosome, and the receptor is recycled to the plasma membrane. Cholesterol is then released and used as required eg for
membrane synthesis, steroid hormone synthesis.
LDL
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high levels of what suppresses LDL receptor synthesis?
cholesterol
80 of 91
decreased synthesis of LDL receptors means what is kept in the blood rather than being taken up by cells?
cholesterol
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which lipoprotein becomes resistant to oxidation through apoA-I and A-II
HDL
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which lipoprotein?
Scavenges cholesterol from cells and other
lipoproteins and returns to the liver, excreted in bile
Scavenges cholesterol from cells and other
lipoproteins and returns to the liver, excreted in bile
HDL
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HMG-CoA reductase reduces HMG-CoA to produce what?
mevalonate
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Prevent cholesterol synthesis in the liver
statins
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Prevent cholesterol uptake from the intestine
Eg. Ezetimibe
Also claimed by commercial dietary products
Eg. Ezetimibe
Also claimed by commercial dietary products
cholesterol absorption inhibitors
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Reduce triglycerides and increase HDL, less effective LDL
fibrates
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lower plasma cholesterol primarily by
inhibiting HMG-CoA reductase (decreasing
cholesterol synthesis
inhibiting HMG-CoA reductase (decreasing
cholesterol synthesis
statins
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lowered intracellular cholesterol leads to what?
increased expression of LDL receptor and increased uptake of cholesterol from the blood
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which statement is false about PCSK9?
implicated in familial haemophilia
90 of 91
PCSK9 inhibition
increases LDL uptake
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Other cards in this set
Card 2
Front
which statement is correct about glycerophospholipids?
Back
sn-1 fatty acid usually saturated sn-2 fatty acid usually mono or polyunsaturated
Card 3
Front
which is not an anionic phospholipid?
Back
Card 4
Front
anionic phospholipids...
Back
Card 5
Front
zwitterionic phospholipids.....
Back
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