Week 2: hyperlipidemia

Question 1

Define major terms: hyperlipidemia, hypercholesterolemia, lipoproteins, apolipoproteins

Answer 1

• hyperlipidemia: elevated lipids int eh blood
• lipoproteins-particles in the blood transporting lipids between tissues
• apolipoproteins-protein components of lipoproteins
• hyperlipoproteinemia-abnormally high level of lipoproteins in blood

Question 2

Describe schematic structures of the major classes of lipids in lipoproteins.

Answer 2

1. cholesterol and cholesterol esters: hydrocarbon, planar 4 ring structure, hydrophobic (esters), amphipathic (OH groups).
2. Triglycerides: 3 long chain fatty acids attached to glycerol
3. phopholipids: 2 long chain FAs and other groups (choline, ethanol amine, serene) attached to glycerol. minor component.

Question 3

Recognize general physical and chemical properties of these lipids (cholesterol/esters, triglycerides, P-lipids).

Answer 3

1. Cholesterol and cholesterol esters: inert and stable, found in membranes, lipoproteins, all tissues. precursor to bile acids, steroids, Vit D. good hydrophobic storage form inside cell.
2. Triglycerides: hydrophobic. found in all cells, made in liver, stored in adipose and muscle. major energy source for body, not for brain though.
3. phospholipids: amphipathic, at surface of membranes and lipoproteins. Made in all tissues, esp. liver. Needed for exporting lipids from liver.

Question 4

Write list of major classes of lipoproteins (based on density) and briefly describe the general function of each class.

Answer 4

Based on density, low to high, which is based on ratio of lipid and proteins

1. chylomicron
2. VLDL
3. IDL
4. LDL
5. HDL

Question 5

Describe general structure and physical properties of lipoproteins and apolipoproteins.

Question 6

List or recognize names of major diseases associated with hyperlipidemia.

Answer 6

• cardiovascular disease, atherosclerosis, CAD, MI, stroke
• obesity, DM, ischemic colitis, metabolic syndrome
• pancreatitis, pancreatic cancer, nonalcoholic fatty liver disease
• xanthoma (cutaneous fatty deposits), xanthelasma (eyelids)

Question 7

List or recognize the major sites (tissues) where lipoproteins and endogenous cholesterol synthesis occurs.

Answer 7

-lipoproteins: made in small intestines and liver in the well fed state.
Sources of cholesterol
-diet: limited ability to absorb cholesterol from diet (200-300mg/day)?
-endogenous: made in liver and intestines from carbs, amino acids, FAs.