Exam 3: Citric Acid Cycle Flashcards
What is an obligate anerobe
only grows in absence of O2, uses fermentation
what an aerotolerant anaerobe?
grows in absence of O2, can tolerate some ROSs only uses fermentation
Facultative anerobes
can use anaerobic and aerobic metabolism
obligate aerobes
need O2, aerobic metabolism, can ferment things but cant survive with that
Where does the citric acid cycle happen
in the matrix or space inside the mitochondrial membrane
What is the purpose of the CAC
to convert glucose pyruvate into CO2 and produce NADH and FADH2
What is NAD
nicatinamide dinucleotide vitamin not produced by body
How many electrons do NAD+ and NADH have
NAD+ 10 e-
NADH 12e-
What is Delta E not
change in reduction potential
What does a small and a large delta E not mean
small: more negative, low affinity for e-
large: more positive, high affinity for e-
do reactions in the CAC tend to have larger or smaller delta E not
larger, more negative, higher affinity for e-
What is FAD/ FMN
flavin adenine dinucleotide or flavin mononucleotide both made of riboflavin
How many electrons do FAD/FMN have and FADH2/FMH2
FAD/FMN: 10e-
FADH2/FMH2: 12e-
What is CoASH coenzyme A
non protein organic mol that carries acetyl groups
When in the CAC is CoAsh used
acetyl CoA to citrate
Where on CoAsh can acetyl group be attached
thioester bond btween 4 phosphopantetheine and 3’ phosphoADP
What kind of rxn is the fist rxn in CAC, catalyzed by citrate synthase
condensation rxn
What kind of rxn is rxn 2 catalyzed by aconitase
isomerization
What kind of rxn is rxn 5 with enzyme succinyl CoA synthase
substrate level phosphorylation
What enzyme is highly regulates in CAC and is the only enzyme in mitochondrial membrane
succinate dehydrogenase
What kind of rxn is rxn7 with fumerase
hydration, isomerization
What are the 3 primary enzymes regulated in CAC
citrate synthase, isocitrate dehydrogenase, alpha ketoglutarate
Why is the CAC amphibolic, what else feeds into and out of it
both anabolic and catalytic, can go to gluconeogenesis, can go to AA metabolism both ways (fatty acids and heme) . Can come from pyrimidines and AAs (Asp), or Glu
Which enzymes in CAC catalyze oxidative decarboxylation rxns?
isocitrate dehydrogenase and alpha ketogluterate dehydrogenase complex
The pyruvate dehydrogenase complex catalyzes the
conversion of pyruvate from glycolysis to acetyl CoA which enters the CAC
Which enzyme is the only membrane bound enzyme in the CAC
succinate dehydrogenase
which enzyme is not a control point of the CAC
aconitase
