Exam 3 – Dr. Sullivant Lipid Metabolism

Question 1

What are the types of lipids?

Answer 1

Triglycerides
Phospholipids
Cholesterol

Question 2

What are fatty acids?

Answer 2

The basic moiety of all lipids

They are long chain hydrocarbon organic acids

Question 3

What are triglycerides used for?

Answer 3

Primarily energy production

Question 4

What is the composition of triglycerides?

Answer 4

3 fatty acids and 1 glycerol

Question 5

What are cholesterol and phospholipids used to do?

Answer 5

Make cell membranes

Question 6

What are lipoproteins?

Answer 6

A carrier service for lipids in the plasma

Question 7

What do lipoproteins do?

Answer 7

Transport lipids to and from liver

Transport lipids to other tissue for use/storage

Question 8

What are lipoproteins made of?

Answer 8

Cholesterol
Triglycerides
Phospholipids
Protein

Question 9

What are the types of lipoproteins?

Answer 9

Chylomicrons
Low density lipoproteins (LDL)
Very low density lipoproteins (VLDL)
High density lipoproteins (HDL)

Question 10

What do chylomicrons do?

Answer 10

Carry digested fat from intestines to lymphatics

Question 11

What do LDLs contain?

Answer 11

Higher cholesterol

Question 12

What do VLDLs contain?

Answer 12

High triglycerides

Moderate cholesterol

Question 13

What do HDLs contain?

Answer 13

Lower cholesterol

Question 14

What is bile made by?

Answer 14

Hepatocytes at a rate of 1/2 to 1 liter/day

Question 15

Where is bile stored?

Answer 15

Gall bladder

Question 16

What are the 2 major functions of bile?

Answer 16

Fat digestion

Excretion of wastes, including cholesterol and bilirubin

Question 17

What is the composition of bile?

Answer 17

Bile salts make up 50% of composition

Question 18

What are bile salts made from?

Answer 18

Cholesterol

Question 19

When is bile released from the gall bladder?

Answer 19

When fat reaches the duodenum

Question 20

What is the contraction that releases bile stimulated by?

Answer 20

Cholecystokinin

Question 21

What do bile salts do?

Answer 21

Emulsify fat globules and then form micelles that allow further digestion/absorption of fats

Question 22

What happens to bile salts once the emulsify fat globules?

Answer 22

They are left behind in the GI tract lumen and recycled back to the liver for repeat use

Question 23

What does an increase in chylomicron in the serum after a meal do?

Answer 23

Causes turbidity or whitish color

Question 24

How long does it take for chylomicrons to be cleared in normal animals?

Answer 24

Within 30 minutes

Question 25

Describe micelles

Answer 25

Have water soluble and fat soluble portions that surround the fat
Allow water soluble enzymes to act further on fat for digestion Shuttle broken down fats to the intestinal brush border and release them into the intestinal cells

Question 26

What does lipoprotein lipase do?

Answer 26

Break down chylomicron to release triglycerides and free fatty acids immediately

Question 27

What are the steps of lipid metabolism?

Answer 27

Lipolysis
β-oxidation
TCA cycle
Oxidative phosphorylation

Question 28

What happens in lipolysis?

Answer 28

Triglycerides hydrolyzed to FA and glycerol

Question 29

What does hormone sensitive lipase do?

Answer 29

Signals the release of stored fat from adipose when cells need energy
Turns stored fat into free FA in the bloodstream

Question 30

What are the ketones?

Answer 30

Acetoacetic acid
β hydroxybutyric acid
Acetone

Question 31

What does the liver do if lipid concentrations are too elevated?

Answer 31

It degrades the excess fatty acids into kets-acids (ketones)

Question 32

What does insulin do?

Answer 32

Increases CHO utilization and fat storage

Increased fat mobilization for energy

Question 33

What activates hormone sensitive lipase?

Answer 33

Epinephrine
Glucocorticoids
Growth hormone

Question 34

What does leptin do?

Answer 34

Signal satiety to hypothalamus
Decreases fat storage
Decreases appetite

Question 35

What is leptin produced by?

Answer 35

Full adipocytes