Lecture 25 Flashcards
(26 cards)
What is the form that most fats take?
TG
What type of fat is TG?
They are neutral fats because they dont have charged groups in their chemical structures.
What happens to excess carbs?
It can be stored as glycogen and made into TG and stored for later
Where is fat stored?
adipocytes
What is the function of adipocytes?
play an important role as regulators of energy balance and glucose homeostasis
What is true about fat?
It is more reduced and contains more energy and is less hydrated, lighter in weight
Where does fuel come from in mammals?
- diet
- biosynthesis
- storage in adipocytes
How are TG taken?
They have to be digested because they are too large. They also deal with being insoluble in aqueous environments.
What are bile salts?
Acids synthesized in the liver and stored in the gall bladder. They are derived from cholesterol like cholic acid.
What is true about bile salts?
They are amphipathic. They emulsify fats and break apart large globules and make them accessible to water soluble enzymes
What does lipase do?
Catalyzes the breakdown of fats to fatty acids and glycerol. Lipase digests the triacylglycerols into monoacylglycerols and free fatty acids or diacylglycerols and free fatty acid.
Where is lipase secreted?
duodenum
What happens to lipase and the products after being catalyzed?
The products of this activity can then be absorbed down the concentration gradient via passive diffusion across the intestinal epithelium.
What happens when TGs get to the intestinal cells?
They are resynthesized into newly formed triacylglycerols and accumulate as droplets at the endoplasmic reticulum and Golgi apparatus of those cells.
What is a chylomicrons?
Spherical protein coated fat globules are specialized molecules designed for the transport of lipids in the circulation and have a polar phospholipid surface with proteins and cholesterol also integrated.
What do chylomicrons do?
Chylomicrons transport cholesterol and triacylglycerols from the intestinal mucosa into the lymph system to bodily tissues.
What happens to TG and the chylomicrons when they reach the capillary?
They are hydrolyzed by the lipoprotein lipase which is activated by Apo-C-II
What is clathrin?
a protein that plays a major role in the formation of coated vesicles. It forms a triskelion shape composed of three clathrin heavy chains and three light chains.
What is the problem that fat can be used as ATP?
it is impermeable and has to use acetyl coA
What is the cartinine shuttle?
responsible for transferring longchain fatty acids across the barrier of the inner
mitochondrial membrane to gain access to the enzymes of beta-oxidation
What is the order of lipoproteins from most to least dense?
chylomicrons, VLDL, IDL, LDL, HDL
What is true about lipoproteins?
they are less dense than proteins
How does Apo-B-100 work?
hydrolysis of TG of chylomicrons and VLDLs. Apo-B-100 is reused to synthesize LDLs by liver
What is LDL used for?
transport cholesterol to tissues
