Cholesterol

Question 0

Where does cholesterol synthesis occur?

Answer 0

Cytoplasm

Question 1

RLS of cholesterol synthesis

Answer 1

HMG-CoA –> mevalonate

HMG-CoA reductase

Question 2

MOA of statins

Answer 2

Competitive inhibitor of HMG CoA reductase

Question 3

Effect of insulin and glucagon on cholesterol synthesis

Answer 3

Insulin dephosphorylates –> activates

Glucagon phosphorylates –> inactivates

Question 4

Primary bile acids

Answer 4

Cholic acid

Chenodeoxycholic acid

Question 5

Conjugated primary bile acids become?

Answer 5

Conjugation with TAURINE or GLYCINE

Bile acids –> bile salts

Question 6

Secondary bile acids

Answer 6

Deoxycholic acid

Lithocolic acid

Question 7

Where are bile acids and bile salts absorbed

Answer 7

Terminal ileum 95%

Question 8

MOA of cholestyramine

Answer 8

Bile acid sequestrant

Bind bile acids in the gut, preventing their reabsorption, promoting excretion

Question 9

Lipoprotein with lowest density and largest size

Answer 9

ChyLOmicron

Think: malaking LOBO

• largest size = most lipid
• lowest density = magaan = least protein

Question 10

Densest lipoprotein

Answer 10

HDL

Question 11

Apolipoprotein necessary for activation of lipoprotein lipase

Answer 11

Apo C-II

II = LL = lipoprotein lipase

Question 12

Function of lipoprotein lipase

Answer 12

Degrades TAGs within the chylomicron

Question 13

Degradation of TAGs form what products

Answer 13

Fatty acids –> stored by adipose or used by muscle

Glycerol –> used by liver

Question 14

Stimulus for lipoprotein lipase synthesis

Answer 14

Insulin - fed state

Question 15

Where is VLDL produced

Answer 15

Liver

Question 16

Function of VLDL

Answer 16

Carry triglycerol from the liver to the peripheral tissues

In the periphery, it will be degraded by lipoprotein lipase also

Question 17

Who donates Apo C-II and Apo-E?

Answer 17

HDL

Question 18

As the VLDL exists the liver as nascent VLDL, what apoprotein does it carry?

Answer 18

Apo B-100

Question 19

Primary function of LDL

Answer 19

Provide cholesterol to peripheral tissues or to return it to the liver

Question 20

What receptors do peripheral tissue recognize?

Answer 20

Apo B-100

Question 21

To whom does HDL give Apo C-II and Apo E

Answer 21

Chylomicrons

VLDL

Question 22

Function of Apo E

Answer 22

Required for receptor mediated endocytosis of IDLs and chylomicron remnants to the liver

Question 23

Cholesterol immediately esterified by — when it is taken up by HDL

Answer 23

PCAT or LCAT
phosphatidylcholine: cholesterol acyltransferase
Or lecithin

Question 24

Responsible for reverse cholesterol transport

Answer 24

HDL Cholesterol from peripheral cells --> to HDLs --> to liver for bile acid synthesis or disposal via bile

Question 25

Activates nascent HDL

Answer 25

Apo A-I

Question 26

Abetalipoproteinemia - deficiency?

Answer 26

Apo B-48 (chylomicrons) and Apo B-100 (VLDL, LDL) Intestinal malabsorption with accumulation of lipids in intestines and liver

Question 27

Familial lipoprotein lipase - deficiency?

Answer 27

Lacks lipoprotein lipase - unable to degrade High VLDL and chylomicron levels in plasma Xanthomas and pancreatitis No increased risk for CAD

Question 28

Familial Hypercholesterolemia - deficiency?

Answer 28

LDL receptors High LDL levels in blood These receptors are important for uptake by liver in tissues Xanthomas and xanthelasmas Increased risk for CAD

Question 29

Activates LCAT to produce cholesterol esters

Answer 29

Apo A-1

Question 30

Where are chylomicrons assembled

Answer 30

Intestinal mucosal cells (from dietary lipids - primarily triglycerol)

Question 31

Primary component of nascent VLDL

Answer 31

Triacylglycerol

Question 32

When peripheral tissues endocytose LDLs, what happens?

Answer 32

Contents are degraded in the lysosomes

Question 33

Where are HDLs synthesized

Answer 33

Liver and intestines

Question 34

Responsible for esterifying cholesterol from other lipoproteins

Answer 34

HDL Using PCAT/ LCAT

Question 35

After esterifiation of cholesterol via PCAT/ LACT, what happens

Answer 35

It is activated by Apo A-1 and delivered to the liver (aka reverse cholesterol transport)

Question 36

Deliver cholesterol to liver for elimination

Answer 36

HDL

Question 37

Deliver cholesterol to peripheral tissues

Answer 37

LDL

Question 38

Deliver de novo TAG to peripheral tissues

Answer 38

VLDL

Question 39

Deliver dietary TAG to peripheral tissues

Answer 39

Chylomicrons

Question 40

Lowest TAG content

Answer 40

HDL

Question 41

Highest TAG content

Answer 41

Chylomicrons

Question 42

Highest cholesterol content

Answer 42

LDL

Question 43

Lowest cholesterol content

Answer 43

Chylomicrons

Question 44

Role of exogenous chenodeoxycholic acid

Answer 44

Increases cholesterol solubility in bile, acting like an emulsifying agent

Question 45

Once glycerol (product of lipoprotein lipase degradation) is produced, what will happen?

Answer 45

It is converted to DHAP and enters glycolysis or gluconeogenesis

Question 46

What activates pancreatic lipase

Answer 46

Trypsin | Found in intestinal lumen

Question 47

What activates hormone sensitive lipase?

Answer 47

Glucagon During fasting Found in the liver

Question 48

Highest protein content

Answer 48

HDL | 'Heavy'