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une ch 20
tricarboxyclic acid cycle
Question | Answer |
---|---|
TCA intermediates/compounds: Our City Is Kept Safe and Sound From Malice | Oxalacetate Citrate Isocitrate alpha-Ketoglutamate Succinyl-CoA Succinate Fumarate Malate |
Enzymes involved in cycle: CAIK Sounds So Fucking Mint. | Citrate synthase Aconitase Iso-citrate dehydrogenase Alpha-Ketoglutarate dehydrogenase Succinyl-coA synthetase Succinate dehydrogenase Fumerase Malate dehydrogenase |
Name the four dehydrogenase enzymes of the TCA cycle. Which are control enzymes? | Isocitrate dehydrogenase, Alpha-ketogluterate dehydrogenase, Malate dehydrogenase are all control enzymes. The other is succinate dehydrogenase |
Isocitrate dehydrogenase | Isocitrate + NAD+ --> a-ketoglutarate, NADH + H+ + CO2 |
Alphaketogluterate dehydrogenase: | a-ketoglutarate + NAD+ + CoASH --> Succinyl-CoA + NADH + H+ + CO2 |
Succinate dehydrogenase: | Succinate + FAD <--> Fumarate + FADH2 |
Malate dehydrogenase: | Malate + NAD+ <--> Oxaloacetate + NADH + H+ |
Name the 5 cofactors of alpha-ketoglutarate dehydrogenase reaction. | Never Cared For Licking Those Netherregions Prinkly Red Naked Tasty NAD, CoASH, FAd, Lipoate, TPP, Niacin, Pantothenate, Riboflavin, None, Thiamine |
Name five pathways which use TCA cycle intermediates as substrates. What is the effect of these pathways on the TCA cycle? | All Flower Girls Have Brains 1. Amino acid synth(uses Oxaloacetate and alpha-ketoglutarate) 2. Fatty acid synth(uses Citrate) 3. Gluconeogenesis (uses Malate) 4. Heme synth(uses Succinyl CoA) 5. Brain neurotransmitter synth (uses alpha-ketoglutarate) |
how is the rate of the TCA cycle linked to muscle contraction and utilization of ATP? | when you flex- atp dec, adp/amp inc.inc atp stimulates isocitrate dh and alphaketo dh in TCA to make NADH.TCA cycle stimulated by dec NADH/NAD ratio2provide more NADH/FAD2H. messengers from ETC tell ATP about atp rate of use. faster TCA=more ATP4muscles. |
how does the calcium concentration affect the TCA cycle? | it is the feed forward activator for two control enzymes (isocitrate dh and alphak dh) and more NAD converted to NADH |
when brain uses energy, explain what happens to all of the ratios... | ATP/ADP ratio dec, inc in ADP (inhibits PDC kinase), NADH/ NAD ratio dec, ACOA inc, inc CA (more pyruvate converted to aCoA by PDC resulting in more ATP being produced by TCA) |
explain how muscle contraction is related to rate of pyruvate dh reaction | inc Ca2+ -> activates PDC phosphatase->dephosphorylates PDC putting it into active form-> active PDC will convert pyruvate to ACoA for use in TCA cycle-> will make ATP for muscle contraction- |
explain what activates PDC and (in)activates it | inc NADH, inc aCOa due to PDC kinase phosphorylation. inc ADP, inc pyruvate= pdc phosphatase dephosphorylates= inc pdc |
which vitamins would you prescribe to be positive that the pyruvate dehydrogenase and the pyruvate carboxylase reactions would have an adequate amount of cofactors? | *Pyruvate Carboxylase: Biotin *Pyruvate Dehydrogenase: Riboflavin, Thiamine, Pantothenate, and Niacin (lipoate is synthesized in body; no vitamin required) |
how does calcium affect the tca cycle? | calcium is a feed foward activator of the two control enzymes. as calcium inc, more NAD converted to NADH by isocitrate DH and alphaK DH |
what are the effects of inc NADH and A CoA on PDC? | inc NADH and ACOA will activate pdc kinase phosphorylation and dec PDC |
what are the effects of inc adp and pyruvate on the pdc? | inc adp and inc pyruvate will allow for pdc phosphate to dephosphorylate and inc pdc |
what is the effect of calcium on PDC? | inc calcium leads to inc PDC phosphatase and then PDC is active. |
additional pies of calcium tase me nary acrid decreases kiwi's | inc adp and pyruvate and calcium activate pdc phosphatase (and inc adp inhibits pdc kinase) whereas inc nadh and inc acoa inc pdc kinase and pdc is deactivated |
cal and aldy activates dh to convert and terry sees amt goes down so shes speeds up | calcium activates iso dh and alphakg dh to convert nad to nadh. tca cycle is stimulated by low nadh/nad ratio |