Lipids Skildum

Question 1

Most calorically dense food?

Answer 1

Fat

Question 2

What particle functions to promote cholesterol homeostasis?

Answer 2

HDL

They take excess cholesterol from the tissues back to the liver where it can be converted into bile salts etc.

Question 3

Which lipoprotein activates an extracellular lipase in capillary beds?

Answer 3

ApoCII

*Activates lipoprotein lipase

Question 4

What can we do with excess de novo glucose in our bodies?

Answer 4

Make Fatty acids!

Question 5

Main storage form of energy in our body?

Answer 5

Triacylglycerol

Question 6

Key intermediate between fatty acids and prostaglandins & leukotrienes and thromboxanes?

Answer 6

Arachidonic acid!

Question 7

How do prostaglandins and thromboxanes play into achalasia?

Answer 7

They can chemically signal a tonically contracted LES

Question 8

What acts to break up fat down into a lot of little tiny globs of fat?

Answer 8

Bile acid salts

Question 9

Where are lipases secreted from?

Answer 9

pancreas

Question 10

At what point does fat composition change after swallowing?

Answer 10

In the small intestine

Question 11

What hormones promote secretion of bile and lipases into the lumen of the gut?
*Cause contraction

Answer 11

Secretin & Cholecystokinin (CCK)

Question 12

Why do people with CF often have malabsorption of lipids?

Answer 12

Secretion of lipases is deficient because of pancreatic duct blockage

Question 13

Where does pancreatic lipase cut on triacylglycerol?

Answer 13

1 and 3 positions

Question 14

What is the end product of pancreatic lipases function?

Answer 14

2 fatty acids + 2-monoacylglycerol

Question 15

What do the products of pancreatic lipase combine with once taken up by gut epithelial cells before they become chylomicrons that enter the lymph system and then the blood?

Answer 15

ApoB48

Question 16

What are the products of cholesterol esterase?

Answer 16

Cholesterol and a free fatty acid

Question 17

Positions of fatty acids on phospholipids?

Answer 17

1 and 2 positions

Question 18

What is fat consumed as phospholipids broken down by?

Answer 18

PLA2

Question 19

Major apoprotein produces by gut epithelial cells?

Answer 19

ApoB48

Question 20

So what things go from the lumen to the blood and what goes from the lumen to the lymph?

Answer 20

Amino acids and glucose go into the blood

Chylomicrons go into the lymph (they bypass portal blood that goes directly into the liver)

Question 21

Main difference between chylomicrons and VLDL?

Answer 21

Apoprotein composition: chylomicrons ApoB48, VLDL has ApoB100

Question 22

What produces ApoB48 in intestinal epithelial cells?

Answer 22

RNA Editing…The full length unedited transcript of the B-apoprotein gene produces ApoB-100

Question 23

Structure of chylomicron?

Answer 23

Phospholipid outside
TAG on inside
ApoB48 acts as a nucleus that these things coalesce around

Question 24

Nascent chylomicron?

Answer 24

ApoB-48 only

No metabolic fate

Question 25

How are nascent chylomicrons matured?

Answer 25

Addition of other apoproteins that are donated by HDL...HDL gives then ApoCII and ApoE

Question 26

Role of ApoCII?

Answer 26

allow chylomicron to deliver fatty acids to different tissues...LipoProteinLipase on extracellular side of capillary bed contacts ApoCII and fatty acids are taken up by tissue!

Question 27

Where is LPL located?

Answer 27

Capillary beds of muscle and adipose tissue

Question 28

When chylomicrons lose most of their fatty acids what happens?

Answer 28

Become chylomicron remnants and are reuptaken by the liver! Recycled

Question 29

Role of VLDL?

Answer 29

Release fat that is produced by dietary carbohydrate

Question 30

How does VLDL go from nacent to competent?

Answer 30

It has to pick up peripheral lipoproteins like ApoCII and ApoE from HDL

Question 31

What happens when VLDL is floating in the blood?

Answer 31

ApoCII interacts with LPL (just like a chylomicron) and you get FA cleavage...FA enter cell. If it is an adipose cell, it is being repackaged as TAG but if it is a muscle cell it will be oxidized for fuel

Question 32

Order of LDLs in terms of fat content

Answer 32

VLDL >IDL >LDL >HDL *HDL has much more protein and less fat

Question 33

What particle functions to distribute dietary fat to tissues?

Answer 33

Chylomicron

Question 34

Which particle functions to distribute fat synthesized from carbs to tissues?

Answer 34

VLDL