Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Cardiovascular > Cholesterol and Lipid Metabolism > Flashcards

Cholesterol and Lipid Metabolism Flashcards

1
Q

describe the solubility of lipids

A

insoluble, or sparingly soluble, in water

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

what are lipids essential for?

A

membrane biogenesis

membrane integrity

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

what are the roles of lipids?

A

energy sources
precursors for hormones
signalling molecules

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

give two non polar lipids?

A

cholesterol esters

triglycerides

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

how are non polar lipids transported in the blood?

A

within lipoproteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what are the types of lipoproteins?

A

high density lipoproteins (HDL)
low density lipoproteins (LDL)
very low density lipoprotein (VLDL)
chylomicrons

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

what is the difference in lipoproteins in people with CV disease?

A 
elevated LDL (or particles rich in triglycerides)
decreased HDL
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what are the causes of the difference in lipoproteins in people with CV disease?

A

diet and lifestyle

genetic factors eg familial hypercholesterolaemia

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

what do lipoproteins consist of?

A

a hydrophobic core and a hydrophilic coat

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

describe the hydrophobic core of lipoproteins

A

contains esterified cholesterol and triglycerides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

describe the hydrophilic coat of lipoproteins

A

a monolayer of amphipathic cholesterol, phospholipids and one, or more, apoproteins

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

which apoproteins do HDLs contain?

A

apoA1 and apoA2

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

which apoprotein do LDLs contain?

A

apoB-100

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

which apoprotein do VLDLs contain?

A

apoB-100

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

which apoprotein do chylomicrons contain?

A

apoB-48

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

what is the role of apo-B containing lipoproteins?

A

deliver triglycerides to muscle for ATP biogenesis and adipocytes for storage

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

where are chylomicrons formed?

A

intestinal cells

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

what is the role of chylomicrons?

A

transport dietary triglycerides

the exogenous pathway

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

where are VLDL particles formed?

A

liver cells

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

what is the role of VLDL particles?

A

to transport triglycerides synthesised in that organ

the endogenous pathway

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

summarise the life cycle of apo-B containing liposomes

A

assembly
intravascular metabolism (involving hydrolysis of the triglyceride core)
receptor mediated clearance

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

how are triglycerides in chylomicrons formed?

A

monoglycerides combine with free fatty acids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

how are cholesteryl esters in chylomicrons formed?

A

cholesterol combines with NCPC1L protein and esterifies

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

how are chylomicrons assembled?

A

triglyceride combines with apoB48

MTP and lipidation are used

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
what is an enterocyte?
an intestinal cell | the site of chylomicron assembly
26
how do chylomicrons exit enterocytes?
by exocytosis following the addition of a second apoprotein (apoA1)
27
how are chylomicrons carried to the systemic circulation?
they enter the lymphatics and is crammed in lymph via the thoracic duct
28
what is MTP?
microsomal triglyceride transfer protein
29
where are the components that form chylomicrons derived from?
digestion of dietary fat and bile
30
where are the fatty acids that form VLDL particles derived from?
adipose tissue and de novo synthesis
31
describe the assembly of VLDL particles
MTP lipidates apoB100 forming nascent VLDL that coalesces with triglyceride droplets
32
how are chylomicrons and VLDL particles activated?
by the transfer of apoCII from HDL particles
33
what is lipoprotein lipase (LPL)?
a lipolytic enzyme associated with the endothelium of capillaries in adipose and muscle tissue
34
how are apoB containing lipoproteins metabolised?
ApoCII facilitates binding of the lipoproteins to LPL which hydrolysis core triglycerides to free fatty acids and glycerol which enters tissues
35
what are the particles depleted of triglycerides but still containing cholesteryl esters termed?
chylomicron and VLDL remnants
36
what is the role of LPL?
causes the particles to become relatively enriched in cholesterol due to triglyceride metabolism
37
what is apoE?
a high affinity ligand for receptor mediated clearance
38
what happens once the apoB containing lipoproteins dissociate from LPL?
apoCII is transferred to HDL particles in exchange for apoE remnants return to the liver and are further metabolised by hepatic lipase all apoB48 remnants and half apo100 remnants are cleared by receptor mediated endocytosis into hepatocytes
39
what happens to the remaining apoB100 containing remnants?
they lose further triglyceride through hepatic lipase, become smaller and enriched in cholesteryl ester and via intermediate density lipoproteins become LDL particles lacking apoE and retaining solely apoB100
40
what is the clearance of LDL particles crucially dependant upon?
the LDL receptor expressed by the liver and other tissues | clearance by the liver is most important
41
how does cellular uptake of LDL particles occur?
receptor-mediated endocytosis
42
how is cholesterol released in the cell?
at the lysosome, it is released from choleryl ester by hydrolysis
43
what does released cholesterol cause?
inhibition of HMG-CoA reductase which is the rate limiting enzyme in de novo cholesterol synthesis down regulation on LDL receptor expression storage of cholesterol as cholesterol ester
44
why is LDL the bad cholesterol?
because at the start of atherosclerosis, LDL from the blood is uptaken into the intima of the artery and oxidised into atherogenic oxidised LDL
45
what initiates atherosclerosis?
dysfunction and injury of the lining of blood vessels
46
why is HDL the good cholesterol?
it plays a key role in removing excess cholesterol from cells by transporting it in plasma to the liver only the liver has the ability to eliminate cholesterol from the body
47
where is HDL formed?
mainly in the liver
48
how is HDL formed?
initially as apoA1 in association with a small amount of surface phospholipid and unesterified cholesterol (disc like pre-B-HDL) this matures in the plasma to spherical a-HDL as surface cholesterol which is enzymatically converted to hydrophobic cholesterol ester that migrates to the core of the particle
49
how does HDL deliver cholesterol to the liver?
it accepts excess cholesterol from the plasma membrane of cells and transports it via transport cholesterol tranport
50
what happens once HDL reaches the liver?
it interacts with a receptor (scavenger receptor B1) that allows transfer of cholesterol and cholesteryl esters into hepatocytes
51
what does cholesterol ester transfer protein (CETP) do?
in the plasma it mediates the transfer of cholesteryl esters from HDL to VLDL and LDL, indirectly returning cholesterol to the liver
52
what is the classification system of primary dyslipidaemia?
Frederickson
53
what causes primary dislipidamia?
a combination of diet and genetic factors
54
what causes secondary dislipidaemia?
it is a consequence of other diseases eg type II diabetes, hypothyroidism, alcoholism, liver disease
55
name examples of statins
simvastatin and atorvastatin
56
how do statins reduce cholesterol?
act as competitive inhibitors of HMG-CoA reductase which is the rate limiting step in cholesterol synthesis in hepatocytes decrease in hepatocyte cholesterol synthesis causes a compensatory increase in LDL receptor expression and enhanced clearance of LDL
57
when are statins ineffective
in homozygous familial hypercholesterolaemia where LDL receptors are lacking
58
when are fibrates used?
in patients with very high triglyceride levels
59
name fibrates
bezafibrate | gemfibrozil
60
how do fibrates act?
they are agonists of a nuclear receptor (PPARalpha) which enhances the transcription of the gene that encodes for LPL
61
name bile acid binding resins
colestyramine colestipol colsevelam
62
how do bile binding resins act?
they cause the excretion of bile salts resulting in more cholesterol to be converted to bile salts by interrupting enterohepatic recycling
63
what do binding resins cause?
decreased absorption of triglycerides and increased LDL receptor expression
64
how does ezetimibe act?
it inhibits NPC1L1 transport protein in enterocytes of the duodenum, reducing the absorption of cholesterol
65
what does ezetimibe cause?
a decrease in LDL with little change in HDL

Cardiovascular (31 decks)

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