Lipids

Question 1

Describe the process of plaque formation.

Answer 1

Physical damage to endothelium →

Damaged endothelium expresses adhesion molecules →

Lipoprotein particles (LPL) stick to adhesion, signal macrophage recruitment →

Macrophages move into arterial wall and phagocytose LPLs →

Macrophages turns into a foam cell and begin accumulate into waxy hardened strip

Question 2

Lipoprotein particles serve as a sink for _____.

Answer 2

Calcium

Question 3

Causes of Coronary Heart Disease

Answer 3

Genetic (familial hyperlipidemia)

Comorbid with T2DM/metabolic syndromes

Driven by lifestyle (inactivity, smoking)

Question 4

Purpose of fatty acids

Answer 4

Used as rapid energy source when carbohydrates are limitng

Question 5

Purpose of triglycerides

Answer 5

Synthesized from 3 FA and alpha-glycerophosphate

Enables longterm storage nd transport of FAs between liver, adipose, and intestine

Question 6

Purpose of phospholipids

Answer 6

Central component of cell membranes and lipoprotein particles

Question 7

Purpose of cholesterol

Answer 7

Essential component og cell membranes

Used for the synthesis of bile acids/salts

Used to make many hormones

Most cholesterol is synthesized in the liver

Question 8

Purpose of cholesteryl esters

Answer 8

Preferred form of cholesterol for transport in blood

Biologically inert cholesterol for storage in cells

Significantly more hydrophobic than cholesterol

Question 9

How are free fatty acids transported?

Answer 9

Transported in serum bound to albumin proteins

Endogenous pathway: transported from adipose tissue to liver

Question 10

Purpose of bile acids

Answer 10

Solubilize dietary lipids, allowing them to be packaged into chylomicrons

Synthesized in the liver

~95% reabsorbed through intestine into the liver through the port system

Question 11

Definition of chylomicrons

Answer 11

Large lipoprotein particles transport dietary fats from the gut in form of TG

Synthesized in the intestine

Docking apolipoprotein - B-48, C-II, C-III

Question 12

Exogenous pathway of lipid transport

Answer 12

Ingest dietary lipid →

Bile secreted to intestine, forming chylomicrons →

Chylomicrons taken up into blood, encounter lipoprotein lipase (LPL) →

LPL hydrolyzes chylomicron to release FFAs to be taken up by cells →

Chylomicron remnants absorbed by liver

Question 13

Endogenous pathway of lipid transport

Answer 13

To deploy lipids to the tissues, the liver incorporates FFAs drom the adipose tissues, and synthesizes

VLDLs → IDLs → LDLs → tissues

LDLs can be reabsorbed by liver

Question 14

Major classes of lipoprotein particles

Answer 14

Cholymicrons

VLDLs

IDLs

LDLs

HDLs

Question 15

Lipoprotein particles are composed of…

Answer 15

outer “coating” (PLs and unesterified cholesterol)

inner “core (TGs, cholesterol esters)

embedded apolipoproteins (dock with cellular receptors)

Question 16

Definition of VLDLs

Answer 16

Synthezised in the liver

Transport TGs from liver to nonhepatic tissues

Generate IDLs and LDLs

Docking apolipoprotein - B-100

Question 17

Definition of LDLs

Answer 17

Produced by VLDL catabolism (LOL and hepatic lipase HL)

Core is mostly cholesteryl esters

Transports cholesterol to tissues

Eventually reabsorbed by liver by LDL-R in liver

Docking apolipoprotein - B-100