kreb cycle Flashcards
what does high energy/ high ATP tell the TCA cycle?
to stop
would increase in ATP/NADH/GTP/ Succinyl CoA inhibit or activate the TCA cycle?
inhibit- tells the cell to slow down because it does not need to make any more energy
what are the common activators of the TCA cycle?
calcium and ADP
What are the 4 regulated enzymes?
citrate synthetase, isocitrate dehydrogense, alpha ketogluterate dehydrogenase, succinate dehydrogenase
how is citrate synthatase activated?
by substrate availabilty
what inhibits citrate synthetase?
ATP, NADH, succinly CoA and fatty acyl CoA
what is citrate synthetase activated by?
calcium and ADP
what is isocitrate inhibited by?
ATP, NADH
What is isocitrate activated by?
ADP, Calcium
what is special about alph ketoglutarate?
it requires the same coenzymes as pyruvate dehydrogenase
what activates alpha KG dehydrogenase?
calcium
what inhibits alpha KG dehydrogenase?
ATP, GTP, NADH, and succinyl CoA
what activates succinate dehydrogenase?
ADP, inorganoc phosphate and succinate (negative feedback)
what inhibits succinates dehydrogenase?
OOA the end product
will the inhibition of one enzyme stop the TCA cycle completely?
yes
What does citrate inhibit in glycolysis?
PFK-1
why is citrate important for the TCA cycle?
it generates energy
how much ATP is generated in glycolysis?
8
How much ATP is generated from PDH?
2 NADH = 2x3=6ATP
How much ATP is generated by the TCA cycle?
24 (6 NADH =3x6=18 + 2 FADH2= 2x2=4) and have to multiple by two because we have 2 pyruvates
where is FADH2 and NADH produced?
in the matrix
what can produce acetyl CoA?
triglycerides(free fatty acid, beta oxidation), glycogen (glucose, oxidation, glyolysis), protein (amino acids, proetolysis, deamination of oxidation)
what is the first molecule that is formed from the loss of CO2?
alpha keto glutarate
what is the second molecule formed from the loss of C02?
Succinyl CoA
if have a deficiency in making the enzyme that link glycolysis and the TCA cylce, what will be lost?
30 ATP
if pyruvate dehydrogenase is absent what will happen?
pyruvate will be stuck and the TCA cycle will not be able to start
if pyruvate dehydrogenase is absent, what is the fates of pyruvate?
there is an increase in lactate, alanine, no Acetyl CoA, and reduction in ATP
what are the clinical features of pyruvate dehydrogenate dificency?
lactic acidosis, neurologic defects, myopathy, usually fatal at early age
what enzymes will thiamine deficiency change?
alpha KG dehydrogenase in the TCA cycle and pyruvate dehydrogenase in glycolysis
what does asernic posioning bind to and inhibit in the TCA cycle?
lipolic acid
why is it bad that arsenic acid binds to lipolic acid?
because lipolic acid is needed for the activity of dihydrolipoyl transacetylase (e2) needed for the TCA cycle
what result in the inhibition of dihdrolipoyl trasacetylase (E2)?
lactic acidodsis, neurological defects, brain and can lead to death
what other enzyme does arsenic affect?
alpha KG DH and branched chain ketoacid DH
what inhibits aconitase?
fluroacetate
what are the vitamin deficiencies in the citric acid cycle?
niacin (B3), riboflavin (B2), thiamine (B1), panthothenate-CoA, Cobalamine
what does malonate inhibit?
succinate dehydrogenase
what is the hereditary mitochondrial diseases that has a defect in NADH dehydrogenase (ETC)?
leber’s hereditary optic neropathy
what does the hereditary mitochondrial disease affect?
TCA, ETC, Beta ocidation of fatty acids
what are the 2 mitocondrial myopathies going to affect?
oxidative wanting atp tissues, brain, heart and liver
what are the 3 mitochondrial myopathies?
kearns-sayre syndrome, MELAS syndrome ( mitochondrial myopathy, lactic acidosis, and stroke like episodes), MERRF syndrome ( myoclonic epilepsy; ragged red fibers)
what is characterized as ragged red fibers?
mitochondrial disorders
what can stain a mitochondrial disorder?
succinic dehydrogenase stain in the inner mitochondrial matrix
what is a good mitochondrail marker?
succinic dehydrogenase stain
