Dietary Lipids and Digestion

Free fatty acids absorbed by peripheral tissues enter B-oxidation to form

Acetyl-CoA

The initial digestion of lipids occurring in the small intestine begins with

Acid lipases

Free fatty acids cleaved from TAG's by LPL

Are absorbed by peripheral tissues/Are repackaged into TAG's for storage

The formation of micelle formation in the small intestine from disgested lipids is aided by

Bile

Amphipathic membrane lipids include all of the following EXCEPT:

Cholesterol Includes: Diacylglycerols Cholesterol Sphongosine

The chylomicron remnant is

Composed of dietary cholesterol and chiolesterol esters Bound to ApoE which aids in receptor-mediated endocytosis in the liver The product of LPL digestion of TAGs

Excess lipids is feces, also known as steatorrhea, is caused by

Decreased bile salts

Lipoprotein lipase is an extracellular enzyme that is responsible for transporting TAG's into peripheral tissues.

Digests TAGs into free fatty acids and glycerol.

Free cholesterol and short chain free fatty acids are

Directly absorbed by intestinal mucosal cells

ApoE is a recognized receptor on chylomicrons and signals uptake into the perioheral tissues for digestion.

False. ApoE is on chylomicrons and chylomicron remnants and is recognized by receptors on the liver which triggers receptor-mediated endocytosis where it is broken down.

Cholycystokinin (CCK) triggers the release of bile and other digestive enzymes from the pancreas.

False. Bile is released from the gallbladder and not the pancreas.

Membrane lipids such as cholesterol esters, diacylglycerols, and sphingosines are amphipathic.

False. Cholesterol esters are non-polar.

In response to lipids, intestinal mucosal cells secrete hormone sensitive lipase (HSL) to initiate lipid digestion.

False. Cholycystokinin-CCK

Chylomicrons are lipoproptein particles that are composed of a monolayer of amphipathic lipids that have an equal lipid to protein ratio.

False. Chylomicrons have the greatest lipid to protein ratio,

Free fatty acids (FFA) and glycerol are transported into the liver and metabolized to form glucose.

False. FFA's are absorbed by tissues and glycerol is transported to the liver.

Monoacyl glycerols, cholesterol, and long chain free fatty acids from micelles are absorbed by intestinal mucosal cells and transported through the cell into the blood for further repackaging in the liver.

False. Monoacyl glycerols, cholesterol, and long chain free fatty acids are used to resynthesize cholesterol esters and triacylglycerols to be packaged into chylomicrons which transport frmo the lymph then to general circulation.

Which of the following is NOT true about chylomicrons?

Have and equal lipid to protein ratio.

Diet aids such as Orlistat decrease fat absorption in the small intestine by

Inhibiting gastic and pancreatic lipases

Ingested lipids include all of the following EXCEPT:

Phospholipids Includes: TAG Cholesterol Free fatty acids

Which of the following is not resynthesized in the intestinal muscosal cells to form cholesterol esters and triacyl glycerol?

Short chain free fatty acids

Which of the following is NOT true about lipoprotein lipase (LPL)?

Synthesis of LPL is increased by glucagon.

Lipid digestion occurs primarily in the small intestine where pancreatic enzymes break down dietary lipids into free fatty acids, cholesterol, and monocacylglycerol.

True.

Short chain fatty acids are directly absorbed by intestinal muscosal cells and are transported through the blood boud to albumin.

True.

Short chain free fatty acids

Travel through the blood bound to albumin

The role of CCK in lipid degestion is to

Trigger the release of bile from the gallbladder

The primary products of lipid digestion in the small intestine are mixed micelles.

True

Apoproteins function to identify lipoproteins used for receptor-mediated uptake, serving as "address" label.

True.

Chylomicrons are transported from the intestinal mucosal cells into the lymph because they are too big to fit directly into the blood stream which it takes longer for peripheral tissues to receive dietary lipids.

True.

Free fatty acids (FFA) can be repackaged into TAGs for storage or can enter B-oxidation to form Acetyl-CoA.

True.

Glycerol feeds into the glycolytic pathways or travels to the liver to enter the gluconeogenic pathway.

True.