TCA cycle Flashcards
the TCA cycle occurs in what part of the cell?
mitochondrial matrix
Where does the Acetyl-CoA oxidation occur?
mitochondrial matrix
What is Acetyl-CoA oxidation?
Oxidation of pyruvate by pyruvate
dehydrogenase complex (PDC) to
produce acetyl-CoA which is oxidised in TCA cycle
Acetyl-CoA is oxidised into ??? to produce electrons (through energy release) to feed electron transport chain via NADH and
FADH2
CO2 molecules
Function of CoA is to
to carry and accept acetyl groups
conversion of pyruvate to Acetyl-CoA is catalysed by ???
pyruvate dehydrogenase complex
conversion of pyruvate to Acetyl-CoA using pyruvate dehydrogenase complex is located in the ???
mitochondrial matrix
Conversion of pyruvate to acetyl-CoA requires how many enzymes?
5 enzymes
which Thiamine pyrophosphate (TPP), lipoyllysine, and FAD are
prosthetic groups covalently bound to ???
pyruvate dehydrogenase complex
Lipoic acid is covalently linked a lysine residue to give ???
lipoyllysine
what uses substrate channeling?
the pyruvate dehydrogenase complex
why does the PDC use substrate chaneling?
- intermediates of reaction are tethered to surface
- maintains high substrate concentration
- prevents “theft” of activated acetyl group by other enzymes
As a prosthetic group of the PDC, Thiamine pyrophosphate (TPP) uses which vitamin as a cofactor?
Vitamine B1
elevated level of pyruvate in the blood is often an indicator of defects in ???
pyruvate oxidation.
TRUE or FALSE: the TCA Generates
* 3 NADH
* 1 FADH2
* 1 GTP
TRUE
succinate dehydrogenase is
located in the ??? membrane
inner mitochondrial
TCA step 1: C_C bond formation to make ???
citrate
Step 2: Isomerization via ???
cis-aconitate
Step 3: Reaction of isocitrate to a-ketoglutarate with enzyme ???
isocitrate dehydrogenase
step 4: dehydrogenation of a-ketoglutarate to succinyl-CoA involves the enzyme ???
a-ketoglutarate dehydrogenase
Steps 3 and 4 are important because they produce ??? via oxidative carboxylations
Oxidative decarboxylations to give 2 NADH
Which enzymes catalyse the two
oxidative decarboxylation steps (3&4) in the TCA cycle? gives 2 NADH
isocitrate dehydrogenase and a-ketoglutarate dehydrogenation
Step 5: Substrate-level phosphorylation to give ???
GTP
Step 6: Dehydrogenation to give reduced ???
FADH2
Step 7: Hydration of fumarate to ???
malate
Step 8: Dehydrogenation to give ???
NADH
Aconitase is the enzyme that catalyses reaction of citrate to ???
isocitrate
Aconitase contains an iron-sulfur (Fe-S) centre as its coenzyme
which acts in both binding of the
substrate and in the catalytic addition or removal of ???
H2O
TRUE or FALSE a-ketoglutarate dehydrogenase is very different to pyruvate dehydrogenase complex
FALSE
Carbon atoms of CO2 are from ???–>a-ketoglutarate–>succinyl-CoA
isocitrate
anaplerotic reactions are those that ??? the TCA cycle
replenish the TCA cycle
At which steps is NADH produced?
3, 4, 8
at what step is GTP produced?
step 5
At what step is FADH2 produced?
step 6
TRUE or FALSE: Malate Dehydrogenase is found found in both the mitochondrion and the cytoplasm
TRUE
Malate dehydrogenase helps shuttle NADH into mitochondrion by the cytoplasmic version using up NADH to convert ??? to malate which is transported to mitochondrion where mitochondrial version oxidises malate –> ??? to recreate NADH
oxaloacetate