Fat Transport Flashcards
True or False: During fat transport, fatty acids are resynthesized into TAGs in the ER.
True
True or False: In the Golgi, TAGs are packaged into large complexes of lipids and proteins (lipoproteins)
True
_______ transport dietary fats and cholesterol from the _______ to other ______.
Chylomicrons
Intestine
Tissue
______ transport endogenous/recycled fats from the _______ to other ______.
VLDLs (Very-Low-Density Lipoproteins)
Liver
Tissue
True or False: Cells that need fats do not need to have specific cell-surface receptors that bind to chylomicrons or VLDLs
False
What is the role of lipases?
Lipases are associated with cell-surface receptors and release fatty acids from chylomicrons and VLDLs
What is the anatomical structure of a lipoprotein (chylomicron and VLDLs)?
- hydrophobic core of TAGs and cholesteryl esters (like lipid droplets)
- Core is surrounded by cholesterol, apolipoproteins, phospholipids
- Like lipid droplets, it has a phospholipid monolayer
What is the role of apolipoproteins?
- Target lipoproteins to specific tissues
- Activate enzymes that work with lipoproteins
How many different apolipoproteins are there?
~10 diff apolipoproteins
What is the predominant structure of apolipoproteins?
Amphipathic a-helices
True or False: Chylomicrons transport dietary fats and cholesterol from the intestine to adipose, muscle, and heart tissue. Chylomicron remnants are released into blood and absorbed by the liver.
True
True or False: VLDL transport endogenous/recycled TAGs and cholesterol from the liver to other tissues. VLDL remnants are released into blood and some are absorbed into the liver, while others mature into IDL and LDL.
True
Where is HDL produced?
In the liver
What is the role of HDL?
It transports cholesterol from muscle/organs back to the liver
What are the 5 main classes of lipoproteins?
- Chylomicrons
- VLDLs
- IDL
- LDL
- HDL
Which lipoprotein is least dense?
Chylomicron
Which lipoprotein is most dense?
HDL
Which lipoprotein is largest?
Chylomicron
Which lipoprotein is smallest?
HDL
True or False: Chylomicrons directly enter the bloodstream.
False - chylomicrons enter the lymph system before entering the bloodstream.
How are chylomicrons released in the lymph system?
They are packaged into secretory vesicles and released into the lymph system via exocytosis
When is glucagon released?
fasting/low energy state, so glucose in the liver can be released from alpha cells in the pancreas
Glucagon binds to ____ and stimulates the production of ____ and ____
GPCR
cAMP
PKA
PKA leads to phosphorylation of _______ and ______ _______ ________.
- perilipins
- hormone sensitive lipase
