Energy production ~ Lipids Flashcards
(13 cards)
what are the various classes of lipids
- fatty acid derivatives
- hydroxyl-methyl-glutaric acid derivatives
- vitamins
give examples of fatty acid derivatives of lipids
fatty acids
triacylglycerols
phospholipids
eicosanoids
what do eicosanoids do
they’re local mediators
give examples of lipid vitamins
A,D,E,K
give examples of hydroxyl-methyl-glutaric acid derivatives
ketone bodies
cholesterol
cholesterol esters
bile acids and salts
describe the properties of triacylglycerols
hydrophobic
stored in anhydrous form in adipose tissue
glycerol molecule bonded to 3 fatty acid chains
fuel molecules
what controls the storage of triacylglycerols
hormones
insulin promotes it
storage reduced by glucagon, adrenaline, cortisol, growth hormone, thyroxine
how is dietary triacylglycerol processed to produce energy
hydrolysed by pancreatic lipase in the small intestine to produce fatty acids and glycerol. requires bile salts and colipase ( a protein factor)
describe the process of lipolysis
when under stress the body hydrolyses the adipose tissue triacylglycerols using hormone-sensitive lipase, releasing fatty acids and glycerol.
activated by adrenaline, glucagon, growth hormone, cortisol and thyroxine and inhibited by insulin
what is beta oxidation
the process by which fatty acids are oxidised to release energy
occurs in mitochondria
why does beta oxidation not occur in the CNS
because fatty acids do not readily cross the blood-brain barrier
how are ketone bodies synthesised
synthesised in the liver mitochondria by lyase and reductase enzymes which are controlled by the insulin/glucagon ratio
describe the insulin/glucagon ratio during ketone body formation
when the ratio is high (more insulin) lyase enzyme is inhibited, reductase enzyme is activated and cholesterol synthesis takes place.
when the ratio is low (glucagon is high) reductase is inhibited and lyase is activated and causes ketone bodies to be produced
