21: Lipids And Lipoproteins

Question 1

What are isoprenoids

Answer 1

Things made form IPP, like steroids, lipid-soluble vitamins, and other lipid-based products

Question 2

Carbons in acetyl CoA vs IPP

Answer 2

Acetyl coA: 2C

IPP: 5C

Question 3

How does acetyl coA enter cytoplasm from mito?

Answer 3

Citrate shuttle

Question 4

Sterane

Answer 4

Four fused rings that form cholesterol

Question 5

Where is the one hydroxyl group of cholesterol

Answer 5

C3

Question 6

Most abundant sterol

Answer 6

Cholesterol

Question 7

How is cholesterol degraded

Answer 7

Must be used or excreted by liver

Question 8

Biosynthesis of cholesterol is inversely proportional to what?

Answer 8

Dietary intake

Question 9

What does IPP stand for?

Answer 9

Isopentenyl pyrophosphate

Question 10

Where is HMG-CoA reductase located in the cell?

Answer 10

ER membrane

Question 11

Myotoxic side effect of statins

Answer 11

Statin-mediated myopathy due to depletion of CoQ10

Question 12

What does the enzyme ACAT do?

Answer 12

Esterify cholesterol into cholesterol esters

Question 13

What does SRE stand for?

Answer 13

Sterol regulatory element

Question 14

4 Function of lipoproteins

Answer 14

1. Vehicles for transporting cholesterol/cholesterol esters/TAGs/fat-soluble vitamins
2. Cholesterol homeostasis
3. Signaling
4. Activate various enzymes

Question 15

Outer shell vs inner core of lipoproteins

Answer 15

Outer shell: monolayer of phospholipids, free cholesterol, and apolipoproteins
Inner core: TAGs, cholesterol, cholesterol esters

Question 16

ApoC-II function

Answer 16

Activates capillary lipoprotein lipase

Question 17

ApoE

Answer 17

Facilitates uptake into liver

Question 18

ApoA-1 function

Answer 18

esterifies cholesterol

Question 19

Major carrier of cholesterol in blood

Answer 19

LDL

Question 20

How many cholesterol esters are in one LDL

Answer 20

1500

Question 21

LDL function

Answer 21

Transport cholesterol to peripheral tissues

Question 22

HDL is crucial for maturation of what?

Answer 22

Chylomicrons

Question 23

What does HDL do to LDL in periphery?

Answer 23

Scavenges and removes LDL from periphery and transports it to liver to be processed

Question 24

ABCA1

Answer 24

Cholesterol transport protein in endothelial cells and macrophages for LDL transport

Question 25

Useful properties of HDL

Answer 25

Antioxidant, anti-inflammatory, antithrombotic, NO-inducing

Question 26

How to increase HDL levels?

Answer 26

Weight loss, exercise, smoking cessation

Question 27

Normal levels of cholesterol

Answer 27

130-200 mg/dL