the citric acid cycle

Question 1

where does the TCA cycle occur?

Answer 1

mitochondria

Question 2

what is the purpose of the cycle?

Answer 2

convert acetyl-CoA to H2O +CO2 +energy
energy is generated in the forms of ATP, NADH, FADH2

Question 3

what is a pneumoic to remember the steps of TCA cycle?

Answer 3

Citrate Is Kreb’s Starting Substrate For Making Oxaloacetate

Question 4

step 1 of TCA cycle

Answer 4

substrate: acetyl CoA and oxaloacetate
enzyme: citrate synthase
product: citrate
claisen condensation
irreversible
first committed step
highly negative deltaG

Question 5

step 2 of TCA cycle

Answer 5

substrate: citrate
enzyme: aconitase
product: isocitrate
removal/addition of water
reversible
isocitrate consumed quickly

Question 6

step 3 of TCA cycle

Answer 6

substrate: isocitrate
enzyme: isocitrate dehydrogenase
product: a-ketoglutarate
oxidative decarboxylation
highly regulated enzyme
mitochondria: NAD+ accepts electrons-> NADH
cytosol/mitochondria: NADP+ accepts electrons-> NADPH for reductive biosynthesis