Dietary Lipids Flashcards
A FA has an 8C tail. What is the class of FA?
Medium-chain FA
How does digestion of short and medium-chain FAs differ from that of long and very long-chain FAs?
SCFAs & MCFAs do not require bile salts for digestion. They are absorbed directly into the intestine and transported to the liver by albumin.
What is Cholestasis? What is the treatment?
Rection or stoppage of bile floe from the liver resulting in intense itching, dark urine, and light-colored stools. Treatment through diet, medication, or surgery.
How long are short chain FAs?
2-4 carbons
What are the important saturated, long-chain FAs?
Myristic, Palmitic, Stearic acids
Bile salts inhibit pancreatic lipases. How is this prevented?
The pancreas releases colipase with lipases. The colipases bind the lipases and prevent inhibition.
What are the most common FAs?
16 & 18-carbons
What drugs block reabsorption of bile salts to promote production of new salts from cholesterol?
Cholestyramines
What is the importance of Oleic acid?
Lowers risk of heart disease, LDL, & cholesterol
What is the function of Ezetimibe drugs?
Inhibit chylomicron formation to lower cholesterol
Why are long-chain FAs important in the diet?
They are a major source of oxidation for fuel during fasting states and play a vital role in brain and immune system development
How do stains decrease cholesterol?
Inhibit in vivo cholesterol synthesis
What protein on chylomicrons allows docking to lipoproteins and activation of lipases?
ApoCII
What is Cystic Fibrosis? How does the disease affect lipid absorption? What is the treatment?
Genetic mutation in the CFTR that causes thick mucus blocking pancreatic ducks, problems with fat absorption, and fatty stools. No cure, treatment with low long-chain FA consumption and fat-soluble vitamin supplement.
How are short-chain FAs obtained?
They are formed in the intestines by the gut microbiota
What FAs function in inflammation? What about anti-inflammation?
Omega 6 FA - pro-inflammatory
Omega 3 - anti-inflammatory
Lipoprotein lipases are regulated by insulin and enable the release of FAs to be taken up by surrounding cells. What is the activity of LPL on adipocytes, skeletal muscle, and heart muscle when insulin is high?
When insulin is high, the body is in a fed state. LDL activity in adipocytes is increased to store excess FAs. Conversely, LPL activity in the heart and skeletal muscles is low as these cells can rely on glucose in the blood for energy. Low insulin will have the opposite effect on each cell type.
True/False. Only 5% of bile sites are recycled and reused.
False. 95% of bile salts are reabsorbed and recycled in the liver.
How are bile acids formed?
Bile acids are formed in the liver by cytochrome P450-mediated oxidation. Cholesterol is oxidated by 7-alpha-hydroxylase to form cholic acid.
A FA has a 22C tail. What is the class of FA?
Very long chain FA
How many carbons are medium-chain FAs?
5-12 Carbons
What are the 5 types of lipids? How do they differ?
Triacylglycerols - Glycerol backbone with 3 FAs
Glycerophospholipids - Glyercol backbone with 2 FAs and phosphate head group
Ether glycerolipids - Glycero-ether backbone with 1 FA and phosphate head group
Sphingophospholipids - Sphingosine backbone with 1 FA and phosphate head group
Glycolipids - Sphingosine backbone with 1 FA and 1 carbohydrate
What is the importance of Linoleic acid?
Precursor for aracadonic acid, cell membranes, LDL, and cholesterol
The Km for muscle LPL is lower than that of adipose. Why is this?
This ensures that muscle LPL is always saturated, regardless of triglyceride levels.
