proteins and fat metabolism Flashcards
why are lipids a more premium reserve of energy compared to glycogen
because it is hydrophobic and therefore does not require water to be stored alongside it
how much of our protein do we break down and remake each day
300g
can FAs be converted into glucose? Why or Why not?
No
because there is no conversion possible going from acetyl CoA back to pyruvate
what is the amount of fat, protein and glycogen fuel reserve in MJ
400MJ - fat
100MJ - protein
6.5MJ - glycogen
what does the brain use as a substrate for energy during starvation
ketone bodies (derived from FA - but cannot use FA directly)
why are FAs stored as TAG
because free fatty acids are detergents and dangerously acidic
where do the lacteals of the gut drain to
the thoracic duct
how does beta oxidation of FA occur
within the mitochondria (enters mitochondria via carnitine mechanism)
how are free FA transported in the blood
bound to serum albumin
what is the association between FFA and MII
if the amount of FA released exceeds the carrying capacity of serum albumin –> MI following sustained physical stress
which tissues cannot use FA as a fuel
brain
RBCs
testis
explain the regulation of the mitochondria oxidising FA
acetyl CoA is only shuttled into the mitochondria by carnitine when you are in a fasting state (as requires malonyl-CoA - an enzyme that occurs only in the fed state inhibits transferase 1)
how is acetyl CoA used for energy during starvation state
enters the Krebs cycle to make 106ATP per palmitate
what are the ketone bodies
acetoacetate
beta-hydroxybutyrate
acetone
what is the order of preference when using substrates for energy
glucose
protein
fat
why are EPA and DHA essential FA
because they are essential for the retina
positive functions of omega 3
- inhibits thromboxane (antithrombolitic)
- promotes prostacyclin (antithrombolitic)
- inhibits leukotriene synthesis (reduced inflammation)
explain the “nitrogen balance” of children
children - have positive nitrogen balance during growth (more in than out)
which situations will lead to a negative nitrogen balance
starvation burns cancer AIDS surgery
what causes pellagra
niacin deficiency due to a diet primarily consisting of corn which is tryptophan deficiency (niacin precursor)
clinical signs of pellegra
4 Ds:
- photosensitive Dermatitis - Casal’s collar
- Diarrhoea
- Dementia
- Death
why are legumes the richest source of nitrogen in plants
because they fix nitrogen in nodules
corn is deficient in which amino acid
tryptophan
which amino acid can be destroyed with the Maillard reaction
lysine
what is transamination
the link between amino acids and keto acids
what is the alanine cycle used for
to carry excess nitrogen to the liver or kidneys
cause of gout
high levels of uric acid leading to crystals forming and inflammation in the joints predominantly
