14- Dietary Lipids Digestion & Absorption Flashcards
the digestion of lipids begins in the ……….. catalyzed by an …………… lipase
Stomach , acid-stable
1- …….. Lipase that originates from glands at the back of the tongue.
2-…….. Lipase secreted from the stomach cells
1-Lingual
2-Gastric
prerequisite for digestion of lipids
- increases the surface area hydrophobic lipid droplets
- is accomplished by using Bile salts, mechanical mixing, phospholipids
Emulsification
TAG hydrolysis or degradation
1- substrate:
2-enzyme:
3-product:
1-TAG
2-esterase (pancreatic lipase)
3-FA
an anti-obesity drug, inhibits gastric and pancreatic lipases, so it decreases fat absorption resulting in weight loss.
Orlistat
complex and derived lipid digestion (cholesterol)
1-substrate:
2-enzyme:
3-product:
1- cholesterol-ester
2- cholesterol esterase
3- cholesterol + FA
most dietary cholesterol (90%) is present in the …………….. form
free (nonesterified) form
cholesterol esterase activity is greatly increased in the presence of ………
bile salts
complex and derived lipid digestion (phospholipids)
1- are hydrolyzed by ……………
2- requires ………. for optimum activity
(removes FA from a phospholipid)
1-phospholipase A2
2-bile salts
the primary products resulting from enzymatic degradation of dietary lipid are :
1-
2-
3-
(plus fat-soluble vitamins and bile salts (mixed micelle) to facilitate absorption of lipids by intestinal mucosal cells (enterocytes)
1- (2-monoacylglycerol)
2- unesterified cholesterol (free)
3-Lysophospholipids + FA
once the fatty acids are inside the intestinal mucosal cells(enterocytes), they are ……………. to form triglycerides, cholesterol ester, and phospholipids.
re-esterified
the TAG, cholesterol ester and phospholipids along with apoproteins B48 and app-A are incorporated into …………
-secreted from the enterocytes into the blood through the body.
chylomicrons (lipoproteins)
one of the most common harmful genetic disease
-in the pancreas the decreased hydration results in thickened secretions which are not able to reach the intestine, leading to pancreatic enzyme insufficiency.
Cystic fibrosis (CF)
when lipids are boiled with Alkali (NaOH or KOH) they form …….
soaps
saponifiable lipids: 1- 2- Non saponifiable lipids: 3- 4-
1-Simple: Waxes + Triglycerides
2-Complex: Phospholipids + Glycolipids
3-Steroids
4-Prostaglandins
alkali + triacylglycerols (fatty acid esters) —hydrolyzed—> free free glycerol + soap
saponification.
is the number of milligrams of KOH required to saponify (or turn) the fatty acids in one gram of fat into soap
- works on Triacylglycerol
- indicator of FA average molecular weight.
- refers to the amount of esters that can be hydrolyzed into soap(molecular weight measurement)
The Saponification number
the greater the molecular weight (longer carbon chain) , the ………… the saponification number.
smaller
- is the number of milligrams of KOH required to neutralize the free fatty acid presents in one gram of fat or oil
- works on FFA
- quantify the acidity of a substance (measuring the COOH)
- refers to the amount of FFA in the fat/oil(acidity measurement)
Acid value
measure of degree of unsaturation of an oil/fat/wax
- the amount of iodine is taken up by 100 grams of oil/fat/wax
- saturated oils/fats/waxes with zero double bonds can’t take up iodine (zero)
Iodine Value
