Cell metabolism 2 Flashcards
How are fatty acids stored
as triacylglycerols
Why are fatty acids an ideal storage molecule
reduced and anhydrous
Where is acetyl CoA produced
in the mitochondrion
What are the 3 sources of fat
1) diet
2) de novo synthesis by liver
3) storage deposits in adipose
Where are bile salts made and stored
liver and gallbladder
What about bile salts can solublise fats
is hydrophilic and hydrophobic
What does a lack of bile salts lead to
steatorrhea - fat passes through gut undigested
How does orlistat work
inhibitor of gastric and pancreatic lipases
By how much does orlistat reduce fat absorption
30%
for how long is orlistat effective in treating obesity
for 2 years
What are the side effects of orlistat
increased flatus
increased desire to defecate
steatorrhea
abdominal pain
From where do chylomicrons acquire apoproteins
HDL ( high density lipoproteins)
how are digested dietary products absorbed
by enterocytes that line the border of the small intestine
What happens to triglycerides before incorporated into chylomicrons
synthesized by enzymes
From where to where do chylomicrons travel
lacteals of the intestine to the thoracic duct to the left subclavian vein
Where are lipoprotein lipases located
endothelial cells of adipose, skeletal and heart tissue
what happens to fatty acids and glycerol when there are high levels of glucagon
fatty acids undergo beta oxidation
glycerol transported to liver to undergo gluconeogenesis
What do lipoprotein lipases recognise
apoprotein
What does the phospholipid monolayer surround
a core of cholesterol esters and triacyclglycerols
What does the esterification of cholesterol do
makes it even more hydrophobic
Where are cholesterol esters synthesized
plasma
what are the reactants in the esterification of cholesterol esters
cholesterol and phosphatidyl choline
What is the enzyme that catalyses the formation of cholesterol esters
lecithin: cholesterol acyltransferase
What can LDLs be taken up by
macrophages or liver
describe the life cycle of a VLDL
VLDL delivers fatty acids and glycerol to adipose tissue
Becomes a lipid dependent remnant.
It transfers apoproteins to HDL to become a IDL
It gains cholesterol esters from HDL
It becomes a LDL
The LDL is taken up by macrophages (causing atherosclerosis) or by the liver
Why are HDLs called ‘good cholesterol’
take cholesterol from the periphery back to the liver for regeneration of bile salts or disposed of.
Lowers total serum cholesterol
Why are LDLs called ‘bad cholesterol’
prolonged elevation leads to atherosclerosis
why are LDLs called low density
more than 40% of weight made up of cholesterol esters
What is the 1st step needed for the beta oxidation of fatty acids
fatty acid needs to be made into acyl CoA
done by acyl synthetase
ATP hydrolysed to AMP
Describe how the carnitine shuttle works
Acyl CoA transfers Acyl group to carnitine in the presence of carnitine acyl transferase 1 (CAT1)
Acyl carnitine is then transferred into the cytoplasm of the cell by translocase
Acyl Carnitine reacts with CoA to form Acyl CoA in the presecence of carnitine acyl transferase 2 (CAT 2)
