2.3 Digestion of Lipids Flashcards Preview

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Flashcards in 2.3 Digestion of Lipids Deck (37):
0

Know the five roles lipids play in our diet

Energy Source
Increase Texture and palatability of foods
Solubilization and dispersion of flavors
Slow gastric emptying
Essential fatty acids and fat-soluble vitamins

1

Fat digestion occurs where?

Small Intestine

2

90% of dietary lipids are what in what form?

Triacylglycerols

3

What enzyme is found in the mouth that begins emulsification with dietary phospholipids but is not very significant..

Lingual Lipase

4

What lipid enzyme is found in the stomach?

Gastric Lipase

5

What enzyme is used for only short and medium chain FA

Gastric Lipase

6

What is the optimal pH for gastric lipase

pH 7

7

Why is the optimal pH significant for gastric lipase?

Only babies have pH 7 in their stomachs. Therefore, gastric lipase is active in these individuals rather than adults

8

Bile acids are derivatives of what other molecule?

Cholesterol

9

Name the three specific bile acids that are cholesterol derivatives

Cholic Acid (Add H+)
Glycocholic Acid (add Glycine)
Taurocholic Acid (add Taurine)

10

Where is Bile synthesized and stored?

Synthesized in the liver
Stored in the Gallbladder

11

What must happen to lipids before they can be digested by intestinal enzymes

They must be emulsified

12

What is the enterohepatic cycle?

Most bile salts are reabsorbed in small intestine and returned to liver via the portal vein

13

Where is Cholecystokinin released from and is released in response to what?

Released from jejunum in response to chyme in the duodenum

14

Cholecystokinin stimulates what three things?

Stimulates gall bladder to release bile into small intestine
Stimulates pancreas to release digestive enzymes
Stimulates stomach to slow down

15

Where is secretin released and in response to what stimulation?

Released in duodenum in response to low pH of the chyme entering the intestine

16

What is the function of Secretin

To tell pancreas to release a bicarbonate solution to increase pH and neutralize the pH of chyme so that it is not so acidic

17

Name the three pancreatic digestive enzymes

Pancreatic Lipase
Cholesteryl Esterase
Phospholipase A2

18

Function of Pancreatic Lipase

Converts TAGS into 2 monoacylglycerol and FFA

19

Can we absorb monoacylglycerols?

Yes but not Triacylglycerols. THey must be broken down first by pancreatic lipase

20

Function of Colipase

To help stabalize interface between water and fat for pancreatic lipase to function

21

Function of Cholesteryl Esterase

Degrade cholesterol esters to FFA and Cholesterol

22

Is cholesterol an essential nutrient?

No, cholesterol is synthesized in the liver in large quantities

23

Function of Phospholipase A2

Part of the process to remove the 2 FA from phospholipids

24

What activates phospholipase A2?

Trypsin

25

What is the inactivated form of colipase

Procolipase

26

What activates Procolipase

Trypsin

27

What are the two products when Procolipase is activated?

Colipase and Enterostatin

28

Function of Enterostatin?

Cleaved from procolipase it ahas an activity as a satiety signal.

29

Phospholipiase A2 removes a fatty acid from what carbon first? This leaves what product?

C2 (middle carbon)
Product is lysophospholipid

30

What enzyme removes the remaining FA at C1 on Lysophospholipid?

Lysophospholipase

31

What is the final product after Phospholipase A2 and Lysophospholipase have cleaved the two FA from C2 and C1 respectively?

Glycerylphosphorylbase

32

Role of FABP2/I-FABP

To sequester and bind FFA within the intestinal cell

33

What enzyme repackages Cholesterol Esters and Triacylglycerols within the intestinal cell?

Acyltransferase

34

Role of Fatty Acyl CoA Synthetase?

TO add a CoA to a Free Fatty acid within the intestinal cell to trap it in the cell.
Fatty Acyl CoA are the substrates for repacking cholesteryl ester and TAGs

35

T or F, Short and Medium chain FA do not require micelles for absorption. They travel to the liver via portal blood attached to albumin.

True

36

What are the three primary breakdown products of lipid digestion?

FFA
Cholesterol
Monoacylglycerol