Lipids

Question 1

Important function of lipids:

Answer 1

• Cell membrane = maintains membrane fluidity
• Thermal insulator and metabolic regulator
• Hormone synthesis
• Helps absorbs fat soluble vitamins

Question 2

What are the essential fatty acids?

Answer 2

Linoleic and linolenic acids

Question 3

What form are saturated fats in at RT?

Answer 3

Solid

Question 4

What form are unsaturated fats in at RT?

Answer 4

Liquid

Question 5

T/F:

Triglycerides are amphipathic (hydrophilic and hydrophobic parts)

Answer 5

FALSE

Triglycerides are heavily hydrophobic.

Phospholipids and cholesterol are amphipathic

Question 6

What is the main function of a lipoprotein?

Answer 6

Main role is delivery of fuel to peripheral cells—the core is the cargo that is being transported​

Size of lipoprotein correlates with the core neutral lipid content—the bigger the particle, the more content

Question 7

Where are apolipoproteins located?

Answer 7

Primarily on the surface of the lipoprotein particles.

Question 8

What is the function of an apolipoprotein?

Answer 8

They help maintain the structural integrity of lipoproteins and serve as ligands for cell receptors and as activators and inhibitors of the various enzymes that modify lipoprotein particles.

Question 9

What is the major lipoprotein location of Apo A4?

Answer 9

Chylos

Question 10

What is the major lipoprotein location of Apo B100?

Answer 10

LDL

Question 11

What is the main function of LDL and where is is produced?

Answer 11

It reverses cholesterol transport and removed excess cholesterol from peripheral cells.

Synthesized by both the liver and the intestine.

Question 12

What are chylomicrons?Where are chylomicrons produced?

Answer 12

A lipoprotein that transports EXOGENOUS triglycerides (the fats that we just consumed).

It has a hydrophobic core made up of 93% triglycerides and 1% cholesteryl esters.

Produced in the intestine

Question 13

What is the main function of VLDL and where is is produced?

Answer 13

Major carrier of ENDOGENOUS triglycerides.

The hydrophobic core is 65% trig and 8% cholesteryl esters

Produced by the liver

Question 14

What is the main function of LDL and where is is produced?

Answer 14

Involved in the ENDOGENOUS transport of cholesterol from the liver and delivers it to other organs as needed.

Produced from VLDL in blood circulation

Question 15

Which lipid pathway maintains cholesterol equilibrium?

Answer 15

Pathway 4: reverse cholesterol transport pathway.

1 (lipid absorption), 2 (exogenous pathway), 3 (endogenous pathway) all transport dietary lipids and hepatic-derived lipids to peripheral cells.

Question 16

What occurs during the lipid absorption pathway?

Answer 16

Pancreatic lipase converts dietary lipids into more polar compounds with amphipathic properties by cleaving off fat.

Question 17

What are triglycerides converted to during lipid absorption?

Answer 17

monoglycerides and diglycerides

Question 18

What are cholesterol esters converted to during lipid absorption?

Answer 18

Free cholesterol

Question 19

What are phospholipids converted to during lipid absorption?

Answer 19

lysophospholipids

Question 20

___% if of dietary triglycerides are taken up by the intestine

Answer 20

> 90%

Question 21

Key points of the exogenous pathway

Answer 21

initially secrete into the lacteals > lymphatic ducts > enters the circulation via thoracic duct

ApoC2 is found on VLDL and critical for activation of LPL

In the liver the lysosomal break down the remnant particles to release free fatty acid, free cholesterol, and amino acids.

Question 22

Key points of then endogenous pathway

Answer 22

Most that are packaged into VLDL are derived from diet after recircuation from adipose tissue

IDL taken up by liver via Apo E and LDL receptor

Trigs in IDL are removed by hepatic trig lipase which results in LDL production

Question 23

Key points of the reverse cholesterol transport pathway

Answer 23

one major role of HDL is to maintain the equilibrium of cholesterol in peripheral cells by reverse cholesterol transport. It may remove excess cholesterol from cells by multiple pathways.

Question 24

What is the acceptable mac for TC?

Answer 24

TC must be <190

Question 25

Define Arteriosclerosis

Answer 25

The general name for a group of conditions that cause arteries to become thick and stiff

Question 26

Define atherosclerosis

Answer 26

Specific type of arteriosclerosis—plaque, cholesterol and fatty substances build up in your arteries and cause them to narrow. ​

Plaque: This LDL is always in circulation, it will go by an endothelial cell and strip off the electrons which will oxidize the LDL molecule. This is then taken up by macrophages and gets broken down.

Question 27

What labs do you perform when looking arteriosclerosis

Answer 27

TC, HLD-C, LDL-C, and trig

Question 28

What are the two categories of hyperlipoprotenemia?

Answer 28

Hyperlipoproteinemias: diseases associated with elevated lipoprotein level

Hypolipoproteinemias: diseases associated with decreased lipoprotein levels

Question 29

What form of hypercholesterolemia is associated with genetic abnormalities that predispose an individual to elevated cholesterol levels?

Answer 29

Familial hypercholesterolemia (FH)

Question 30

What influences hypertriglyceridemia?

Answer 30

Number of hormones: insulin, glucagon, pituitary growth hormone, ACTH, thyrotropin, epinephrine, norepinephrine

Question 31

____ is the presence of elevated levels of serum total cholesterol and triglycerides

Answer 31

Combined hyperlipidemia

Question 32

Lp(a) elevation combined with elevated LSL increase the risk of ___ and ____

Answer 32

CHD and CVD

Question 33

T/F:

Increased non-HDL-C is associated with increased CVD risk only if LDL-C levels are also elevated

Answer 33

FALSE:

Increased non-HDL-C is associated with increased CVD risk even if LDL-C levels are normal

Question 34

What is the Friedewald calculation?

Answer 34

A method to measure LDL.

LDL-C = TC - HDL - Trig/5