carbs 3 Flashcards
what is the link reaction
pyruvate from glycolysis is converted to acetyl CoA via pyruvate dehydrogenase
what happens if there is a deficiency in pyruvate dehydrogenase enzyme
lactic acidosis
pyruvate can’t be converted to acetyl CoA so take anaerobic pathway instead leading to lactic acid build up
what vitamins provide cofactors for PDH
b vitamins
what does the krebs cycle produce
6 x NADH
2 X FADH2
2 X GTP
what happens in oxidative phosphorylation
NADH and FADH2 from glycolysis and the Krebs cycle are re-oxidised with oxygen to create energy.
the e- from NADH & FADH2 are donated to the ETC within the mitochondrial membrane.
as the e- travel down the energy levels in the ETC they release energy. at the end of the chain the e- combine with oxygen to form water.
the energy from the ETC is used to power proton pumps that move H+ from the matrix of the mitochondria to the intermembrane space. this creates a H+ conc gradient called the proton motive force.
the p.d causes an attractive fierce for the H+ and their only path back in is via the ATP synthase enzyme.
this leads to the phosphorylation of ADP to ATP.
how is oxidative phosphorylation inhibited
inhibitors can block electron transport by blocking the action of oxygen as the terminal acceptor.
no proton gradient formed.
an example is cyandide.
what do uncouplers do to oxidative phosphorylation?
increase the permeability of the mitochondrial inner membrane to protons.
dissipate the proton gradient reducing the proton motive force
no drive for ATP synthesis
brown adipose tissue and uncoupling
uncoupling proteins are activated by NA which is released when body temperature falls
Noradrenaline causes the oxidation of the fat to produce fatty acids, which uncouple ATP synthase, causing the proton gradient (proton motive force) to be dissipated as heat, rather than being used to create ATP.
where is brown adipose tissue found
newborn infants
hibernating animals
