MCP - Turner - Lipids and Their Metabolism - 2/20 Flashcards
How are triglycerides stored?
In an anhydrous state
Compared to carbohydrates, fat provides ___ times the metabolic energy per gram of tissue.
Six
What is the ionization state of fatty acids in vivo?
pKa 4.8, ionization state is negative
T/F: Most human fatty acids have an even number of carbons.
True
How do ionized fatty acids appear in the cell?
They aggregate into micelles.
C14, 0 double bonds, the acid is myristic, the salt is:
myristate,
14:0
C16, __ double bonds, the acid is palmitic, the salt is palmitate.
0
16:0
C16, 1 double bond, the acid is palmitoleic, the salt is:
palmitoleate
16: 1delta9 (location of double bonds)
16: 1omega7
___, 0 double bonds, the acid is stearic, the salt is stearate.
C18
18:0
C18, 1 double bond, the acid is ____, the salt is oleate
Oleic
18: 1delta9 (location of double bonds)
18: 1omega9
C18, ___ double bonds, the acid is alpha-linoleic, the salt is linoleiate
2
18: 2delta9, 12 (location of double bonds)
18: 2omega6
____, 3 double bonds, the acid is linolenic, the salt is linolenate
C18
18: 3delta9, 12, 15 (location of double bonds)
18: 3omega3
C20, 4 double bonds, the acid is arachidonic, the salt is ___.
Arachidonate
20: 4delta5, 8, 11, 14 (location of double bonds)
20: 4omega6
Fatty-acid-derived ____ enters the TCA cycle, yielding ATP and heat.
Acetyl-CoA
T/F: The brain can use free fatty acids for fuel.
False, BBB prevents fatty acid transport
T/F: Fatty acids can be obtained from the diet or synthesized de novo.
True
Excess energy is converted to ___ for storage.
Triglycerides
What are the three main components of bile?
Bile acids (aka bile salts)
Phosphatidyl choline
Cholesterol
How do dietary triglycerides appear as?
Mostly long chain TGs, in which the esterified fatty acids are long chain fatty acids
Where and by what enzyme are the majority of triglycerides digested?
Pancreatic lipase
duodenum and proximal jejunum
The main products of TG digestion are 2-monoacylglycerol (MAG) and NEFA
What are the 3 main causes of steatorrhea?
- Failure of bile production or blockage of bile flow
- Exocrine pancreas dysfunction or obstruction or pancreatic duct
- Failure of uptake into intestinal mucosal cells
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.
trigylcerides
What is the function of acetyl-CoA synthase (also called thiokinase)?
Acetyl-CoA synthase catalyzes formation of acetyl-CoA derivatives of long chain fatty acid
What is the function of acyltransferases?
Acyltransferases, aslo known as transacylases catalyze the transfer of 2 LCFA moieties to 2-MAG
What are chylomicrons?
For transport into the lymph and blood , water-insolube TG must be packaged into a type of lipoprotein particle, called chylomicrons
What is Apo-B48?
Apo-B48 is the principal protein component of nascent chylomicrons as they are produced in the intestinal mucosa
T/F: Chylomicrons and other lipproteins only transport TGs.
False, other lipids are also transported.
Fatty acids are released from lipoproteins by the action of ____ in the capillary endothelial walls of various tissues, especially muscle and adipose tissue.
Lipoprotein lipase
Cleavage occurs at all 3 ester bonds
Products are glycerol and NEFA
T/F: Entry of nonesterified long chain fatty acids from the intestinal lumen into the intestinal mucosa is mediated by protein carriers.
True
A deficiency in lipoprotein would most likely cause abnormalities in:
unloading of free fatty acids from VLDL
What is it called when there is excess lipid in feces?
steatorrhea
Are non-esterified FAs found in the blood?
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.
