Biochem lec 3 - Lipid Metabolism - Metabolism of dietary lipids Flashcards
characteristics of lipids
heterogenous group of water insoluable (hydrpophobic) organic molecules
major source of energy
where does digestion of lipids begin and what is it catalyzed by
begins in stomach
catalyzed by lipase (an acid stable enzyme)
triacylglycerols (TAGS) are the primary targets
where does emulsification of dietary lipids (fats) occur?
small intestine (duodenum)
increases the surface area of the hydrophobic lipid droplets so that digestive enzymes can act effectively
fats are carried out of the small intestine by what
bile salts (hydrophillic points out, hydrophobic will interact w fat)
which pancreatic enzyme degrades TAG
pancreatic lipase
which pancreatic enzyme degrades cholesterol esters
cholesterol esterase
(cholesterol esters to cholesterol and free FAs)
which pancreatic enzyme degrades phospholipids
phospholipase A2 and lysophospholipase
where does degradtion of dietary lipids occur
in the pancrease by pancreatic enzymes
what is too large to be taken up efficiently by the mucosal cells of the intestinal villi
triacylgercol, therefore acted upon by pnancreatic lipase
most dietary cholesterol is present in what form
free form (nonesterified)
what does phospholipase A2 do
removes 1 FA from C2 leaving a lysophospholipid
what does lysophospholipase do
remove the FA at C1 leaving a glycerophosphoryl base
how does cholecystokinin have hormonal control of lipid digestion in the small intestine
stimulates the release of bile and pancreatic enzymes
how does secretin have hormonal control of lipid digestion in the small intestine
secretin stimulates bicarbonoate and water
(helps w synthesis of fatty acids)
what do lipids along w bile salts and fat soluble vitamins form
mixed micelles
(disk shaped clusters of amphipathic lipids that coalesce with their hydrophobic groups on the inside and their hydrophilic groups on the outside
