Lipid Metabolism Flashcards
Chylomicrons
When cholesterol enters the intestinal mucosal cell, it is packaged with triglycerides, phospholipids, and apolipoprotein (A & B48) into a large lipoprotein, the chylomicron
The chylomicron is secreted into the lymph and eventually enters the circulation, delivering triglycerides to the liver and peripheral cells; after being hydrolyzed by lipases into fatty acids
Recognize the specific enzyme deficiency and typical symptoms present in Niemann-Pick
Enzyme deficiency: sphingomyelinase
Symptoms: Large abdomen, within 3-6 months
Feeding difficulties (dysphagia)
Loss of early motor skills (ataxia)
No brain and nervous system development
Recognize the specific enzyme deficiency and typical symptoms present in Tay-Sachs Disease
Enzyme deficiency: hexosaminidase-A
Symptoms: Psychomotor deterioration and dementia
Recognize the specific enzyme deficiency and typical symptoms present in Gaucher’s
Enzyme deficiency: beta-glucocerebrosidase
Symptoms: Hepatosplenomegaly
Bone pain; orthopedic issues
Growth retardation, in children
VLDL
Principle lipoprotein secreted by the liver (containing apo B100 and C-II). The C-II present on the surface of VLDL activates LPL on endothelial cells leading to hydrolysis of triglycerides and release of fatty acids
Differentiate the definitions of arteriosclerosis and atherosclerosis
Arteriosclerosis: a thickening, hardening, and loss of elasticity in artery walls
Atherosclerosis: a form of arteriosclerosis, caused by an accumulation of lipids, complex carbohydrates, etc.
Recognize four detrimental effects of oxidized LDL
- Marcophages are transformed into foam cells
- Cytotoxic effects are exerted on endothelial cells
- Platelet activation is increased
- Migration/proliferation of smooth muscles is stimulated
Recognize the reagents used in Liebermann-Burchard, Abell, and enzymatic cholesterol methods.
Liebermann-Burchard: sulfuric acid and acetic anhydride
Abell: cholesterol esters hydrolyzed to make “free” cholesterol
Enzymatic: cholesterol esterase and cholesterol oxidase
Briefly discuss the exogenous pathway for dietary lipids according to:
a. Its purpose
b. Three important pancreatic enzymes and their substrates
c. The specific site in the intestine where chylomicrons are assembled
a. Transport dietary lipids to the liver and peripheral tissues
b. Lipase: triglycerides
Cholesterol esterase: cholesterol ester
Phospholipase: phospholipids
c. Enterocytes (intestinal cell)
Briefly discuss the exogenous pathway for dietary lipids according to:
d. The importance of mixed micelle formation in the absorption of
dietary cholesterol
e. The importance of apolipoprotein C-II and lipoprotein lipase for
triglyceride hydrolysis
f. Disposition of fatty acids after triglyceride hydrolysis
d. Allows for cholesterol to be emulsified (solubilized) so that it may be transported more easily to be absorbed
e. Apo C-II is located on the surface of the chylomicron activating lipoprotein lipase. Lipoprotein lipase is located on the surface of endothelial cells breaking down triglycerides for uptake by the body
f.
Briefly discuss the exogenous pathway for dietary lipids according to:
g. How the chylomicron remnant is formed
h. The importance of apolipoprotein E for hepatic uptake of the chylomicron remnant
g. After the delivery of fatty acids to the liver and peripheral issues
h. Apo E is required for hepatic endocytosis of the remnant
Briefly discuss the endogenous pathway of lipid metabolism according to:
a. Its purpose
b. The importance of lipoprotein lipase and apolipoprotein C-II in the formation of the VLDL remnant
c. The formation of IDL and LDL
d. The importance of cholesterol ester transfer protein (CETP) in triglyceride-cholesterol exchange
e. The importance of the presence of only apolipoprotein B-100 on LDL
a. Transport of hepatic-derived lipids to the peripheral cells
b.
