L16

Question 1

LDL delivers cholesterol via ____
_______ delivers endogenous fatty acids

Answer 1

Apo-B100
VLDL

Question 2

True or False: LDL delivers endogenously made fatty acids to tissues through the same mechanisms as chylomicrons
VLDL

Answer 2

True

Question 3

Where is LPL most highly expressed?

Answer 3

Capillaries of adipose, skeletal/cardiac muscle

Question 4

How are chylomicrons degraded?

Answer 4

Liver enzymes

Question 5

Binding of ___ to its receptor leads to internalization of chylomicron remnant

Answer 5

Apo-E

Question 6

When do chylomicron remnants form?

Answer 6

After delivery of fatty acids

Question 7

What do chylomicrons have on their surface?

Answer 7

Apo-CII

Question 8

Interactions between what two molecules leads to cleavage of triacylglycerol in chylomicron, releasing fatty acids?

Answer 8

Apo-CII and LPL

Question 9

Chylomicrons containing ___ are taken up into the lymphatic system

Answer 9

Apo-B48

Question 10

What do mature chylomicrons contain?

Answer 10

Fat soluble vitamins and Dietary fat

Question 11

Re-synthesis of what three molecules is REQUIRED for formation of chylomicron re-synthesis?

Answer 11

Triacylglycerol; CE; phospholipids

Question 12

____ deliver dietary fatty acids and have Apo-CII on their surface

Answer 12

Chylomicrons

Question 13

Do chylomicrons delivery exogenous or endogenous dietary fatty acids?

Answer 13

Exogenous

Question 14

What enzyme transfers
resynthesized lipids to Apo-B48?

Answer 14

Microsomal triglyceride transfer
protein (MTP)

Question 15

What is found in inner core of lipoprotein?

Answer 15

CE and TAG (triacylglycerol)

Question 16

The outer core of the lipoprotein contains a single layer of ___ and ___

Answer 16

Phospholipids and Cholesterol

Question 17

___ and __ are the
transport/storage forms of
fatty acids and cholesterol

Answer 17

TAG; CE

Question 18

Lipids are packaged and transported in the
body within vesicles known as ____

Answer 18

lipoproteins

Question 19

Decreasing lipid digestion
and absorption can lead to ____

Answer 19

steatorrhea (oily stool)

Question 20

Which drug inhibits cholesterol absorption in small intestines? How?

Answer 20

• Ezetimibe: blocks NPC1L1 cholesterol transporter on absorptive intestinal cells
• Less cholesterol
  absorbed from diet
  due to inhibition of
  uptake in the intestine

Question 21

Orlistat blocks the actions of ___ and ___

Answer 21

gastric lipase
(stomach) and pancreatic lipase (intestine)

Question 22

How can CF cause EPI?

Answer 22

Buildup of mucus blocks
secretion of enzymes

Question 23

____ facilitate absorption of degraded lipids because its formation allows for penetration of the intestinal water layer

Answer 23

Mixed micelles

Question 24

Absorption occurs at ___ surface of absorptive small intestine cells by ___ proteins

Answer 24

apical ; transport

Question 25

_____ cells are the absorptive cells of the small intestine

Answer 25

“Brush border”

Question 26

Degraded lipids form mixed micelles in the ___

Answer 26

intestine

Question 27

___ and ____ also incorporated into mixed micelles

Answer 27

Bile ; fat-soluble vitamins

Question 28

True or False: Formation of mixed micelles in the small intestine occurs naturally due to hydrophobic regions facing away from the aqueous environment

Answer 28

True

Question 29

___and ____ help coordinate digestion of lipids by signaling to gall bladder and pancreas

Answer 29

Cholecystokinin (CCK) ; Secretin

Question 30

Intestinal cells recognize lipid entering the small intestine and secrete ___ and ___ in response

Answer 30

cholecystokinin; secretin

Question 31

CCK causes gall bladder to release ___ CCK signals to pancreas to secrete ___

Answer 31

bile degradative enzymes

Question 32

LDL has a higher concentration of cholesterol esters and its role is to deliver ______ to ____

Answer 32

cholesterol to cells

Question 33

In LDL receptor mediated endocytosis, cholesterol is either used by cell or esterified by ___and stored

Answer 33

ACAT

Question 34

Mutations in ___ or ___ disrupt the ability of LDL to be internalized and broken down

Answer 34

ApoB-100; LDLR

Question 35

Errors in LDL metabolism can lead to ____of cholesterol in ____

Answer 35

deposition of cholesterol in arteries

Question 36

____returns cholesterol to liver

Answer 36

HDL

Question 37

HDL is predominately made in what two locations?

Answer 37

1) Liver 2) Small intestine

Question 38

True or False: HDL circulates in body and collects excess cholesterol from peripheral (non-hepatic) tissues

Answer 38

True

Question 39

True or False: HDL returns cholesterol to liver for storage, metabolism or excretion

Answer 39

True

Question 40

Newly synthesized HDL is low in ___

Answer 40

cholesterol

Question 41

ApoA1 interacts with ___ ABCA1 transports phosphatidylcholine and free cholesterol to ___ LCAT is activated by __ and uses a fatty acid from phosphatidylcholine to create cholesterol esters

Answer 41

ABCA1 HDL ApoA1

Question 42

___ receptor on liver cells binds HDL and selectively takes up cholesterol esters

Answer 42

SRB1

Question 43

Binding of HDL to ___ allows uptake of cholesterol esters and completes reverse cholesterol transport

Answer 43

SRB1

Question 44

Statins compete with _____. How do they lower cholesterol synthesis?

Answer 44

HMG-CoA - Lead to less HMG-CoA being converted to mevalonate (thereby reducing cholesterol synthesis in the body)

Question 45

Statins upregulate ___ on cell surface, which stimulates more cholesterol internalization from blood

Answer 45

LDL-R

Question 46

____ cholesterol synthesis inhibited by statin

Answer 46

Endogenous

Question 47

_____ bind to bile acids/salts and prevent its reabsorption in small intestine

Answer 47

Bile acid sequestrants

Question 48

Bile acid sequestrants force liver to synthesize more ___ from cholesterol, reducing overall levels of cholesterol

Answer 48

bile

Question 49

Which drugs disrupt enterohepatic circulation leading to less “recycling” of bile salts?

Answer 49

Bile acid sequestrants