Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

FHB Exam 3 > Metabolism: Lipoproteins > Flashcards

Metabolism: Lipoproteins Flashcards

1
Q

Which lipoprotein has the highest protein:lipid ratio? the lowest?

A 
high = HDL
low = chylomicron
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Describe the structure of a lipoprotein.

A

core = TAG and cholesterol esters
membrane = phospholipids and free cholesterol
peripheral apoproteins = exchangeable
integral apoproteins = indicative of lipoprotein type

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

Where are lipoproteins made? What is the difference between these kinds?

A 
liver = endogenous synthesis of TAG, cholesterol
intestines = dietary
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the density of the lipoproteins referring to?

A

density of proteins
HDL = high protein content
hence, HDL is more negative

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

Compare the structures of chylomicrons, VLDL, LDL, and HDL.

A

chylomicrons - largest; lots of TAG
VLDL - next largest; next amount of TAG
LDL - smaller; increase concentration of cholesterol esters:TAG
HDL - smallest; mostly cholesterol esters or free cholesterol

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

What are the reasons for HDL being better than LDL?

A
  • HDL contains less TAG
  • LDL is larger => plaque formation
  • HDL fxn is to remove free cholesterols in the blood whereas LDL delivers cholesterol to peripheral tissues
  • LDLs can be oxidize => plaque formation
  • HDLs are atheroprotective b/c contain antioxidant enzyme to prevent LDL oxidation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the difference between chylomicron and chylomicron remnant function?

A
  • chylomicrons transport dietary TAG from the intestine

- chylomicron remnants have exchanged TAG and sent CE to the HDL and deliver TAG to the liver

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

What changes about the contents of lipoproteins as you go from VLDL => IDL => LDL?

A 
VLDL = mostly TAG
LDL = more cholesterol
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Where do VLDL/IDL/LDL deliver TAG and Cholesterol to?

A

VLDL => TAG to adipose, skeletal muscle, heart muscle,

IDL/LDL => Cholesterol to liver, macrophages, and peripheral cells

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

Describe the chylomicron:

  • source
  • main lipid
  • integral apo
  • function
A
  • made in intestine
  • mainly TAG
  • B48
  • transports dietary TAG to adipose and other tissues
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Describe the chylomicron remnant.

  • source
  • main lipid
  • integral apo
  • function
A
  • made after C2/E exchange with HDL
  • TAG
  • B48
  • delivers remaining dietary TAG to liver
  • exchanges TAG for CE with HDL and delivers those to liver
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Describe the VLDL.

  • source
  • main lipid
  • integral apo
  • function
A
  • liver
  • TAG
  • B100
  • delivers endogenously synthesized lipids to adipose, heart, and skeletal muscle
  • exchanges TAG for CE with HDL
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Describe the IDL

  • source
  • main lipid
  • integral apo
  • function
A
  • VLDL remnant; formed in circulation
  • TAG and cholesterol
  • B100
  • delivers remaining TAG and cholesterol to liver
  • exchanges TAG for CE with HDL
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Describe LDL.

  • source
  • main lipid
  • integral apo
  • function
A
  • IDL remnant; formed in circulation
  • cholesterol
  • B100
  • delivers cholesterol to the liver and other steroidogenic cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Describe HDL.

  • source
  • main lipid
  • integral apo
  • function
A
  • made in the liver
  • cholesterol
  • A1
  • accepts cholesterol from peripheral cells and esterifies it. returns CE to the liver
  • exchanges its CE for TAG from other lipoproteins in circulation
  • atheroprotective peroxonase antioxidant for LDL
  • apoprotein reservoir
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What does LPL do? What is required?

A

LPL = lipoprotein lipases

  • degrades TAGs in lipoproteins marked with C2 to release glycerol and FFAs
  • glycerol goes back to the liver
  • FFAs go to skeletal and cardiac muscle
17
Q

What is the function of B100?

A
  • marks VLDL, IDL, LDL

- binds LDL receptor

18
Q

What is the function of A1?

A
  • marks HDL
  • activates LCAT (cholesterol esterification)
  • binds to HDL receptor
19
Q

What is the function of C2?

A
  • exchanged from HDL to other lipoproteins

- activates LPL

20
Q

What is the function of E?

A
  • exchanged from HDL to other lipoproteins
  • binds to LDR-Receptor-like Protein (LRP)
  • binds to remnant receptor
21
Q

What is the function of B48?

A
  • marks chylomicrons
22
Q

List the development and mechanism of chylomicron function.

A
  1. chylomicrons take dietary TAG from intestines
  2. nascent chylomicrons express B48
  3. apoprotein exchange with HDL => mature chylomicron now also expresses C2 and E
  4. LPL is activated => TAG breakdown, C2 used
  5. remnant chylomicron enters liver via E binding to LRP and LDLR
23
Q

List the development and mechanism of VLDL/IDL/LDL function.

A
  1. liver synthesized TAG are packaged into VLDL
  2. VLDL expresses B100
  3. transient exchange with HDL => VLDL now expresses C2 and E
  4. LPL activated => IDL
  5. IDL is smaller, contains less TAG
  6. LPL activated again => LDL
  7. LDL expresses only B100; C2 and E are returned to HDL
  8. B100 binds to LDLR on peripheral tissues, macrophages, and liver
24
Q

Describe the relationship between cholesterol biosynthesis and LDLR regulation.

A
  • if increased cholesterol biosynthesis (increased cholesterol levels), decreased LDLR (downregulation)
  • if decreased cholesterol biosynthesis (decreased cholesterol levels), increased LDLR (upregulation)
25
Q

How do statins affect LDLR regulation?

A
  • block HMG-CoA reductase
  • decreased cholesterol biosynthesis
  • increased LDLR upregulation
  • increase removal of cholesterol from bloodstream
26
Q

What are the 2 pathways of LDL uptake? Which is the major?

A 
major = LDLR-mediated endocytosis
minor = LDLR-independent uptake by macrophages
27
Q

Why is the minor LDL uptake pathway important?

A

in times of high cholesterol, LDLR-dependent uptake is decreased b/c LDLR is downregulated. But LDLR-independent uptake is still active and contributes to cellular LDL uptake

28
Q

Describe the mechanism by which oxidized LDL contributes to CAD.

A
  1. oxidized LDL uptake by macrophages due to LDLR-independent uptake or oxidized LDLR
  2. cholesterol increase in macrophages => become foam cells
  3. foam cell accumulation and cytokines causes smooth muscle proliferation and calcification
  4. continued LDL uptake leads to atherosclerosis
29
Q

Describe the mechanism of how HDL transport works.

A
  1. nascent HDL with A1, C2, and E made by liver
  2. A1 activates LCAT which esterifies the cholesterol taken up from peripheral cells
  3. mature HDL with cholesterol esters and HDL returns to liver
30
Q

What should your total cholesterol level be?

A
31
Q

Total cholesterol = …

A

HDL + LDL + 20% TAG

32
Q

What should your total HDL be?

A

> 60 mg/dL

33
Q

What should your total LDL be?

A
34
Q

What should your TAG levels be?

A
35
Q

What is the optimal total:HDL ratio?

A

200:60 = 3.3.:1

FHB Exam 3 (23 decks)

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