14- Dietary Lipids Digestion & Absorption

Question 1

the digestion of lipids begins in the ……….. catalyzed by an …………… lipase

Answer 1

Stomach , acid-stable

Question 2

1- …….. Lipase that originates from glands at the back of the tongue.
2-…….. Lipase secreted from the stomach cells

Answer 2

1-Lingual

2-Gastric

Question 3

prerequisite for digestion of lipids

• increases the surface area hydrophobic lipid droplets
• is accomplished by using Bile salts, mechanical mixing, phospholipids

Answer 3

Emulsification

Question 4

TAG hydrolysis or degradation
1- substrate:
2-enzyme:
3-product:

Answer 4

1-TAG
2-esterase (pancreatic lipase)
3-FA

Question 5

an anti-obesity drug, inhibits gastric and pancreatic lipases, so it decreases fat absorption resulting in weight loss.

Answer 5

Orlistat

Question 6

complex and derived lipid digestion (cholesterol)

1-substrate:
2-enzyme:
3-product:

Answer 6

1- cholesterol-ester
2- cholesterol esterase
3- cholesterol + FA

Question 7

most dietary cholesterol (90%) is present in the …………….. form

Answer 7

free (nonesterified) form

Question 8

cholesterol esterase activity is greatly increased in the presence of ………

Answer 8

bile salts

Question 9

complex and derived lipid digestion (phospholipids)
1- are hydrolyzed by ……………
2- requires ………. for optimum activity
(removes FA from a phospholipid)

Answer 9

1-phospholipase A2

2-bile salts

Question 10

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)

Answer 10

1- (2-monoacylglycerol)
2- unesterified cholesterol (free)
3-Lysophospholipids + FA

Question 11

once the fatty acids are inside the intestinal mucosal cells(enterocytes), they are ……………. to form triglycerides, cholesterol ester, and phospholipids.

Answer 11

re-esterified

Question 12

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.

Answer 12

chylomicrons (lipoproteins)

Question 13

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.

Answer 13

Cystic fibrosis (CF)

Question 14

when lipids are boiled with Alkali (NaOH or KOH) they form …….

Answer 14

soaps

Question 15

saponifiable lipids:
1-
2-
Non saponifiable lipids:
3-
4-

Answer 15

1-Simple: Waxes + Triglycerides
2-Complex: Phospholipids + Glycolipids

3-Steroids
4-Prostaglandins

Question 16

alkali + triacylglycerols (fatty acid esters) —hydrolyzed—> free free glycerol + soap

Answer 16

saponification.

Question 17

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)

Answer 17

The Saponification number

Question 18

the greater the molecular weight (longer carbon chain) , the ………… the saponification number.

Answer 18

smaller

Question 19

• 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)

Answer 19

Acid value

Question 20

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)

Answer 20

Iodine Value