Krebs cycle

Question 2

where does Krebs cycle take place?

Answer 2

mitochondrial matrix

Question 3

E1 function of pyruvate dehydrogenase?

Answer 3

catalyses the firstdecarboxylation of pyruvate

Question 4

E2 function of pyruvate dehydrogenase?

Answer 4

transfers the acetyl group tocoenzyme A

Question 5

E3 function of pyruvate dehydrogenase?

Answer 5

recycles the polylysine through the reduction of FAD, which is recycled by passing electrons toNAD+

Question 6

why are the points of control needed?

Answer 6

Blocking isocitrate dehydrogenase causes citratebuild up (isocitrate and citrate areinterconvertable), which shuttles citrate into thecytoplasm causing phosphofructokinase to stopglycolysis– α-ketoglutarate builds up when α-ketoglutaratedehydrogenase is inactive, which switches it’s useto production of amino acids

Question 7

where does terminal respiration/etc occur ?

Answer 7

inner membrane of mitochondria

Question 8

when is the glycol phosphate shuttle needed?

Answer 8

• when cytoplasmic NADH cannot be directly transferred to mitochondria
• when NADH/NAD+ ratio is high and rapid ATP production needed during intense muscle activity