Lipids Flashcards
How much energy is stored as TAGs in the body?
100,000 kcal in the fat and muscle
How are TAGs processed in the GI tract and Intestinal lumen cells?
Dietary TAGs are broken down into monacyl-glycerol and fatty acids (2)
Then they are absorbed by the intestine and assembled back into TAGs
How are chylomicrons (lipoproteins) delivered to the blood from the intestinal luminal cells?
Released into the lymphatics and enter blood stream through the thoracic duct
What is required for liver to undergo de novo synthesis of TAGs?
Glucose/glycerol
What does the liver produce and what does it deliver them to?
Cholesterol, sent to Very Low Density Lipoprotein (VLDL)
From what sources do adipocytes collect lipids?
Either uses circulating glucose to produce TAGs or collects lipids from the circulating lipoproteins
What happens to TAGs in adipocytes when they need to used for energy?
TAGs are broken down into individual fatty acids and delivered the liver bound to albumin.
Once in the liver, the fatty acids undergo beta-oxidation where they will be broken down to acetyl-CoA
What are the 3 major enzymes responsible for breaking down TAGs?
Hormone-sensitive Lipase
Monoacylglycerol Lipase
Lipoprotin Lipase
What signals promote fatty acid mobilization and energy production?
Hunger and Exercise (glucagon and epinephrine)
Both promote hormone-sensitive lipases
What signals prevent fatty acid mobilization and energy production?
Fed State (insulin)
Inhibits hormone-sensitive lipase
What does Peripilin do?
Peripilin is a protein that coats lipid droplets preventing hormone sensitive lipase from having access to the lipids
Blocks Lipolysis
What are the 5 types of Lipoproteins?
Chylomicrons
Very Low Density Lipoprotein (VLDL)
Low Density Lipoprotein (LDL) - Bad Cholesterol
Intermediate Density Lipoprotein (IDL)
High Density Lipoprotein (HDL) - Good Cholesterol
Rank the order of Lipoproteins according to increasing Size
HDL > LDL > IDL > VLDL > Chylomicron
