Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Phase 1 - S2 Metabolism, Endocrinology, Haematology > Lipid transport > Flashcards

Lipid transport Flashcards

1
Q

what are the 5 lipoprotein transporters

A 
chylomicrons
VLDL
IDL
LDL
HDL
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

true or false: lipids are hydrophilic

A

false - they’re hydrophobic which makes them difficult to transport in the blood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

how are fatty acids transported in the blood

A

by being carried by albumin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

how are 98% of lipids transported

A

in lipoprotein particles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

describe phospholipid molecules

A
  • they have a hydrophobic tail made up of 2 fatty acids
  • glycerol backbone
  • phosphate
  • polar hydrophilic head attached to the phosphate
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what part of the phospholipid classifies it

A

the hydrophilic head which can be either choline or inositol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what shape of phospholipids carry aqueous cargo

A

liposome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what shape of phospholipids carry hydrophobic cargo

A

micelle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

where is most of the bodys cholesterol obtained

A

from synthesis in the liver

small amount comes from the diet

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what is cholesterol used for

A
  • for stability in membranes
  • precursor to steroid hormones
  • precursor to bile acids
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

give 4 examples of steroid hormones

A

oestrogen
testosterone
aldosterone
cortisol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

how is cholesterol transported around the body

A

it is converted into cholesterol esters but LCAT enzymes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what are apolipoproteins

A

proteins found either passing through the phospholipid membrane (peripheral) or on the surface (integral) of lipoproteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what are the functions of apolipoproteins

A
  • allows lipoprotein molecule to form by allowing packaging of the water insoluble contents
  • act as cofactors for enzymes to break down lipids
  • act as ligands to receptors to take up cargo
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what does the density of lipoproteins depend on

A

the amount of apolipoproteins on their surface

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

in a flotation ultracentrifugation which lipoprotein migrates the furthest

A

HDL

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

for more dense lipoproteins what happens to the size of their diameter

A

It decreases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what apolipoprotein is added to chylomicrons before they enter the lymphatic system

A

apoB-48

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

when chylomicrons enter the left subclavian vein what other apoproteins are added

A

apoC and apoE

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what does the addition of apoC to chylomicrons allow

A

the binding to lipoprotein lipase on adipocytes and muscle allowing the chylomicrons to release their fat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what do chylomicrons mostly contain

A

dietary fat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

what do VLDL contain

A

TAGs synthesised by the liver

23
Q

what happens to chylomicrons when the TAG content is reduced to 20%

A

the apoC dissociates and the chylomicron becomes a chylomicron remnant

24
Q

what happens to chylomicron remnants

A

they return to the liver and the apoE allows it to bind to LDL receptors on hepatocytes to be taken up by receptor mediated endocytosis

25
where is VLDL synthesised
in the liver
26
what apoproteins bind to VLDL
apoB100, apoC and apoE
27
how do VLDL become depleted
they bind to LPL in the muscle and adipose cells
28
what happens to the fatty acids taken up by muscle and adipose cells
muscle - used in energy production | adipose - resynthesised to TAGs and stored
29
how are IDLs formed
when the TAG content of VLDL drops to 30%
30
how are LDL formed
when the TAG content of IDL depletes to 10% and so loses its apoC and apoE
31
what happens to IDL particles
- can be taken up by the liver | - or can rebind to LPL to be further depleted
32
what is the cholesterol content in LDLs like
very high
33
what is the function of LDL
provide cholesterol from thee liver to tissues
34
how are LDLs taken up by cells
attach to LDL receptor then taken up by receptor mediated endocytosis
35
why aren't LDLs efficiently cleared up by the liver
as Liver LDL receptors have a high affinity for apoE which the LDL doesn't have
36
why do LDLs become oxidisied
they have a long half life so are more susceptible to oxidative damage by free radicals
37
outline receptor mediated endocytosis for LDLs
- LDLs have the apoB100 as a ligand which binds to LDL receptors on cells requiring cholesterol - complex is taken up by endocytosis - fuse with lysosomes for digestion as release of cholesterol and fatty acids
38
how are nascent HDLs synthesised
- by the liver and intestine in low TAG levels - bud off from chylomicrons and VLDL as they're digested by LPL - from apoA1 can aquire cholesterol and phospholipids to form the HDL
39
how are the nascent HDLs filled
- they can accumulate phospholipids and cholesterol from cells lining blood vessels - core progressively fills - this doesn't require enzymes
40
what do HDLs do
remove cholesterol from cells and returns it to the liver
41
what do HDLs reduce the likelihood of
foam cell and atherosclerotic plaque formation
42
what protein facilitates the transfer of cholesterol to HDLs
ABCA1
43
what happens to the cholesterol when it enters HDLs
it is converted into cholesterol esters by LCAT
44
as well as the liver where else might HDLs deliver cholesterol to
steriodogenic cells as they have a scavenger receptor to allow this
45
what protein allows the exchange of cholesterol ester for TAG between HDLs and VLDLs
cholesterol exchange transfer protein
46
what is hyperlipoproteinaemia
where there is raised plasma levels of one or more lipoproteins classes
47
what causes hyperlipoproteinaemia
- over production | - under removal
48
what causes type I, IIa and III of hyperlipoproteinaemia
I - defective lipoprotein lipase IIa - defective LDL receptor III - defective apoE
49
what are the clinical signs of hypercholesterolaemia
- xanthelasma - yellow patches on eyelids - tendon xanthoma - nodules on tendons - corneal arcus - white circle around eye
50
what does raised LDL level cause
- engulfed by macrophages forming foam cells which accumulate in intima to give fatty streak - develops into atherosclerotic plaque - grows and reduces lumen - this can rupture to trigger a thrombosis
51
what are the treatments for hyperlipoproteinaemias
- reduce cholesterol and saturated fat intake - increase fibre - increase exercise - reduce smoking - statins - bile salt sequestrants
52
what do statins do
inhibit HMG-CoA reductase which is used in the production of cholesterol
53
what do bile salt sequestrants do
bind to bile salts in the GI tract so they are egested. this means more cholesterol is needed to make bile salts
54
what can cholesterol tests measure
- total cholesterol level - non HDL level - LDL level - HDL level - triglyceride level - ratio of total cholesterol to HDL

Phase 1 - S2 Metabolism, Endocrinology, Haematology (22 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions