MCP - Turner - Lipids and Their Metabolism - 2/20

Question 1

How are triglycerides stored?

Answer 1

In an anhydrous state

Question 2

Compared to carbohydrates, fat provides ___ times the metabolic energy per gram of tissue.

Answer 2

Six

Question 3

What is the ionization state of fatty acids in vivo?

Answer 3

pKa 4.8, ionization state is negative

Question 4

T/F: Most human fatty acids have an even number of carbons.

Answer 4

True

Question 5

How do ionized fatty acids appear in the cell?

Answer 5

They aggregate into micelles.

Question 6

C14, 0 double bonds, the acid is myristic, the salt is:

Answer 6

myristate,

14:0

Question 7

C16, __ double bonds, the acid is palmitic, the salt is palmitate.

Answer 7

0

16:0

Question 8

C16, 1 double bond, the acid is palmitoleic, the salt is:

Answer 8

palmitoleate

16: 1delta9 (location of double bonds)
16: 1omega7

Question 9

___, 0 double bonds, the acid is stearic, the salt is stearate.

Answer 9

C18

18:0

Question 10

C18, 1 double bond, the acid is ____, the salt is oleate

Answer 10

Oleic

18: 1delta9 (location of double bonds)
18: 1omega9

Question 11

C18, ___ double bonds, the acid is alpha-linoleic, the salt is linoleiate

Answer 11

2

18: 2delta9, 12 (location of double bonds)
18: 2omega6

Question 12

____, 3 double bonds, the acid is linolenic, the salt is linolenate

Answer 12

C18

18: 3delta9, 12, 15 (location of double bonds)
18: 3omega3

Question 13

C20, 4 double bonds, the acid is arachidonic, the salt is ___.

Answer 13

Arachidonate

20: 4delta5, 8, 11, 14 (location of double bonds)
20: 4omega6

Question 14

Fatty-acid-derived ____ enters the TCA cycle, yielding ATP and heat.

Answer 14

Acetyl-CoA

Question 15

T/F: The brain can use free fatty acids for fuel.

Answer 15

False, BBB prevents fatty acid transport

Question 16

T/F: Fatty acids can be obtained from the diet or synthesized de novo.

Answer 16

True

Question 17

Excess energy is converted to ___ for storage.

Answer 17

Triglycerides

Question 18

What are the three main components of bile?

Answer 18

Bile acids (aka bile salts)
Phosphatidyl choline
Cholesterol

Question 19

How do dietary triglycerides appear as?

Answer 19

Mostly long chain TGs, in which the esterified fatty acids are long chain fatty acids

Question 20

Where and by what enzyme are the majority of triglycerides digested?

Answer 20

Pancreatic lipase
duodenum and proximal jejunum

The main products of TG digestion are 2-monoacylglycerol (MAG) and NEFA

Question 21

What are the 3 main causes of steatorrhea?

Answer 21

1. Failure of bile production or blockage of bile flow
2. Exocrine pancreas dysfunction or obstruction or pancreatic duct
3. Failure of uptake into intestinal mucosal cells

Question 22

In the intestinal cell, ____ is resynthesized from 2-MAG and absorbed long chain fatty acids and then packaged into liprotein particles called chylomicrons that are exported into the lymph.

Answer 22

trigylcerides

Question 23

What is the function of acetyl-CoA synthase (also called thiokinase)?

Answer 23

Acetyl-CoA synthase catalyzes formation of acetyl-CoA derivatives of long chain fatty acid

Question 24

What is the function of acyltransferases?

Answer 24

Acyltransferases, aslo known as transacylases catalyze the transfer of 2 LCFA moieties to 2-MAG

Question 25

What are chylomicrons?

Answer 25

For transport into the lymph and blood , water-insolube TG must be packaged into a type of lipoprotein particle, called chylomicrons

Question 26

What is Apo-B48?

Answer 26

Apo-B48 is the principal protein component of nascent chylomicrons as they are produced in the intestinal mucosa

Question 27

T/F: Chylomicrons and other lipproteins only transport TGs.

Answer 27

False, other lipids are also transported.

Question 28

Fatty acids are released from lipoproteins by the action of ____ in the capillary endothelial walls of various tissues, especially muscle and adipose tissue.

Answer 28

Lipoprotein lipase
Cleavage occurs at all 3 ester bonds
Products are glycerol and NEFA

Question 29

T/F: Entry of nonesterified long chain fatty acids from the intestinal lumen into the intestinal mucosa is mediated by protein carriers.

Answer 29

True

Question 30

A deficiency in lipoprotein would most likely cause abnormalities in:

Answer 30

unloading of free fatty acids from VLDL

Question 31

What is it called when there is excess lipid in feces?

Answer 31

steatorrhea

Question 32

Are non-esterified FAs found in the blood?

Answer 32

YES! They can be released from adipocytes as fuel substrates in when burning fat (e.g. aerobic exercise) or upon lipoprotein lipase (LPL) cleavage of TGs in chylomicrons or VLDLs. BUT because they are hydrophobic they must bind to albumin for transport.