Brainscape's Knowledge GenomeTM

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


See full index

Biochem > Exam3Lec2Lipoproteins > Flashcards

Exam3Lec2Lipoproteins Flashcards

1
Q

Definition of lipoproteins

A

transportation form of hydrophobic substances such as lipids

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

Where are lipids derived from?

A

fatty acids

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

What are some examples of lipids?

A

fats, oils, waxes, steroids, sterols

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

What are the functions of lipids?

A
  • Energy source
  • Component of cell membranes,
  • Hormones (cell to cell communication),
  • Insulation for nerves
  • Protection and insulation for organs
  • Vitamin A,D,E, K are lipid soluble
  • Buoyancy
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Why do lipids present a special challenge?

A

lipids are hydrophobic

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

How does the body transport lipids: cholesterol and triglycerides

A

they are transposrted inside a lipoprotiens

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

What is the composition of a lipoprotein particle?

A

core: contains non polar lipids( tri glycerols and cholesterol esters)
outside: amphiphatic lipids (phosholipids heads and cholesterol)
**surface: apolipoprotiens

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

The higher the diameter of the lipoprotein, the___ density

A

lower

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

What is the order of lipoproteins from lowest to highest density?

A

Chylomicrons, VLDL, IDL, LDL, HDL, Fatty acids and Albumin

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

Chylomicron is made of

A

cholesterol:3%
phospholipid: 5%
triacylglycerol: 90%

largest diameter
Most amount triacyglycerol

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

VLDL is made of

A

cholesterol:10%
phospholipid: 10%
triacylglycerol: 70%

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

LDL is made of

A

cholesterol:26%
phospholipid:15%
triacylglycerol: 10%

most amt of cholesterol

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

HDL is made of

A

cholesterol:20%
phospholipid: 25%
triacylglycerol: 5%

smallest diameter

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

What are apoproteins?

A

on surface of lipoproteins to provide structure and function by indentifying receptors on cells its looking to bind to

They recognize receptors on organs so type of apo is essential for lipoprotein fxn and where it transports.

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

What is the fxn of apoprotein?

A
  1. solubility and structural integrity
  2. receptor-binding and targeting
  3. Enzyme activation
  4. Exchange
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is ApoA-1?

A

unique to HDL-Structural and enzyme activator (activates LCAT)

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

What is ApoB?

A

unique to non HDL particles-Structural and ligand for receptor binding

18
Q

What are the major lipoproteins for Apo B-100

A

VLDL, IDL, LDL

19
Q

What are the major lipoproteins for Apo B-48

A

chylomicrons, remnant

20
Q

Explain ApoB mRNA editing.

A

ApoB-48: Cytidine Deaminase Editing complex converts CAA to UAA and makes it a stop codon. Then gets translated into ApoB48 In the INTESTINES.

ApoB-100: no modifications in the liver

no modification in the liver, because it does not have the cytidine deaminase enzyme

21
Q

As a result of RNA editing, where is ApoB-48 and ApoB-100 expressed?

editing ONLY, not splicing, mutation, division, etc.

A

ApoB-48 is expressed only in the intestinal cells and is requored for the receptor to uptake chylomicron remnant in liver

ApoB-100 is expressed only in the liver and is required for LDL uptake by Liver

22
Q

After the small intestine, chylomicron has what ratio of TG to Chol and what two steps can occur.

A

10:1
(a) They can be given up as FFA to tissues
(b) Can be converterted to the Chylomicron remnant (1:1:) by LPL

23
Q

What is LPL?

A

Lipprotein lipase: enzyme required to hydrolyze chlyomicrons and VLDL to free fatty acids (FFA) and 1,2-diacylglycerols (DAG)

24
Q

What is the LPL reaction?

A

Tracylglycerol to 1,2 diacylglycerol + fatty acid

LPL hydrolyzes TG

LPL is located in adipocytes, striated muscles, pancreatic islets, macrophages

25
Q

Overview of chylomicrons
Synthesis location
Secretion location
Contains apoprotein
Function

A
  1. Synthesis location: small intestines in fed state
  2. Secretion location: Lymph vessels to blood vessels
  3. Contains apoprotein: ApoB 48
  4. Function: deliver TAG to body cells to be used as fuel
26
Q

VLDL LCAT reaction

Lecithin-cholesterol acyltransferase

A

Esterifies cholesterol so that it can be easily transported

cholesterol + lecithin turns into cholesterol ester and lysolecithin by LCAT

Adds more cholesterol

27
Q

VLDL ACAT reaction

A

uses acyl-coA to add acyl group to cholesterol in liver

cholesterol + acyl-coA turns to cholesterol ester by ACAT

ACAT is only in liver

`

28
Q

Overview of VLDL
Synthesis location
Secretion location
Primary component
Contains: apoproteins
Fxn

A

Synthesis location: liver
Secretion location: bloodstream
Primary component: rich in TG
Contains: apoproteins ApoB-100
Fxn: deliver TAG to body cells

29
Q

Overview of LDL
synthesis location
Function

low density lipoproteins

A

Synthesis location: liver as VLDL and uses LPL to release all FFA and convert cholesterol to cholesterol esters using LCAT
Secretion location: bloodstream
Primary component: cholesterol
Apoprotein: none
Function: deliver cholesterol to all body cells

30
Q

Explain HDL reverse cholesterol transport

A

removes cholesterol from extra-hepatic tissues (aka body)
1. HDL removes free cholesterol from tissue and transports it to liver for excretion
2. Liver disposes cholesterol as bile acids and free cholesterol
3. HDL is called “good cholesterol”

HDL to VLDL by CETP. VLDL to Remants of VLDL by LPL. Remnants of VLDL to liver

31
Q

What is CETP (cholesterol ester transfer protein)

A

Transfers HDL to VLDL for uptake by the liver

nore that there are differences of ratio betweem triaglycerols and cholesterol ester. And trasnfers can occur.

32
Q

Overview of HDL
Synthesis location:
Secretion location:
Primary component:
Contains:
Fxn:

A

Synthesis location: liver and intestines
Secretion location: bloodstream
Primary component: cholesterol
Contains: apo-A1
Fxn: remove cholesterol from body and deliver to liver “good” form of cholesterol (reverse cholesterol transport).

There is potential to help reverse heart disease

33
Q

What is the general pathway of cholesterol uptake?

A
  1. LDL binding
  2. Internalization
  3. Lysosomal hydrolysis (chol released)
  4. Regulatory actions
34
Q

Cholesterol is taken up via LDL receptors. What regulatory actions can occur?

A
  1. DOWN regulation of HMG CoA reductase: do not need to make more chol. because we just received cholesterol from diet. (this makes chol)
  2. UPregualation of ACAT: meed to store all the cholesterol we just absorbed (acat makes chol. esters)
  3. DOWNregulation of LDL receptors: do not need to take in more cholesterol
35
Q

Organs and pathways involved in plasma lipoprotein metabolism

A

Sources: HEPATOCYTES making VLDL, HDL, and LDL are in the liver. INTESTINE from dietary uptake : Chylomicron is in the Intestine

Sources goes to Lipoprotein transport particle where we see different conversion which then goes to target organs

Target organs: Peripheral (nonhepatic) cell, macrophage, muscle cell, adipocyte

36
Q

Triglyceride and Cholesterol has a protein component: Apolipoproteins. What are the 4 functions

A
  1. Solubility, structual integrity
  2. receptor binding-targeting
  3. enzyme activation
  4. exchange
37
Q

Hyperlipidemia/Hyperlipoproteinemia can lead to what

A

Increaed risk of atherosclerosis and cardiovascular diseases

38
Q

What is familial Hypercholesterolemia

A

genetics: mutation in LDL receptor gene (you lack LDL receptors so there is decr degradation of LDL)
Metabolic characterisitcs: high LDL and plasma cholesterol lvls
Physical characteristics: orange-yellow xanthomas (large amt of LDL accumaulation w/chol bc of no receptor)

note: Liver does not recognize body has too much cholesterol which leads to no down-regulation of HMG CoA reductase, so you keep making chol.

39
Q

Cholesterol is found in what type of food?

A

ANIMAL FOOD ONLY (eggs, red meat, milk, cheese, etc)

does NOT come from fruits, vegetables, grains, etc

40
Q

What atherosclerosis?

A

Plaque formation within endothelial lining of arteries causing blockages in blood flow

41
Q

What is the LDL hypothesis for Atherosclerosis?

A
  1. Elevated lvls of LDL cholesterol and apoB100 directly contribute to atherosclerosis
  2. Oxygen radicals in endothelial lining of the arteries oxidize LDL and retain them
  3. Activated endothelial cells have increased inflammation (macrophages are attached to it)
  4. Macrophages take up LDL and are saturated with cholesterol thus forming foam cells
  5. Hemmorage/tissue damage from plaque micro vessels

Biochem (17 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions