CItric Acid Cycle Flashcards
products of conversion of pyruvate to acetyl CoA?
2 NADH are formed
where does the conversion of pryuvate into acetyl COA
inside the mitocondria
WHERE DOES THE CITRIC ACID CYCLE OCCUR? WHERE DOES OXIDATION PHOSPHORYLATION OCCUR?
BOTH INSIDE THE MITOCONDRIA
eukaryotic cells without mitocondria
mature erhytocytes
3 examples of cells with high energy needs that have a lot of mitocondria as a result
heart for contraction
kidney for transport
liver for biosynthesis
In ____ cells, mitochondria account for up to 20% of the total protein.
liver
The citric acid cycle occurs in the ___ of the mitocondria
matrix
where are oxidative phosphorylation enzymes?
embedded in the inner membrane facing the matrix.
traffic between the cytoplasm and matrix space is controlled by specific transport systems, except for
O2 and CO, which diffuse through
functions of the citric acid cycle (3)
A. Converts a number of different fuels to a common mobile fuel (NADH).
B. Serves as the final meeting place of nearly all oxidizable substrates.
C. Provides intermediates for biosynthesis.
Oxidation of Pyruvate to Acetyl-CoA
first step? what is the prosthetic group?
Condensation and decarboxylation by pyruvate dehydrogenase (E1)
prosthetic group – TPP (thiamine b1)
Oxidation of Pyruvate to Acetyl-CoA
second step? what is the prosthetic group?
Oxidative transfer by dihydrolipoyl transacetylase
prosthetic group – lipoamide
Oxidation of Pyruvate to Acetyl-CoA
third step? what is the prosthetic group?
Transacetylation by dihydrolipoyl transacetylase
prosthetic group – lipoamide
Oxidation of Pyruvate to Acetyl-CoA
fourth step? what is the prosthetic group?
Oxidation of dihydrolipoamide by dihydrolipoyl dehydrogenase
Prosthetic group: FAD
The pyruvate dehydrogenase complex has multiple
Multiple Lipoamides/E2
In the pyruvate dehydrogenase complex
Dihydrolipoamide
______ is the site of action of arsenite poisoning
Importance of Lipoamide as a Swinging Arm in the pyruvate dehydrogenase complex:
Kinetics are fast
___ groups are not going on and off an ezyme, are always there
prosthetic
Acetyl CoA + oxaloacetate + H2O —> ____
by citrate synthetase
citrate + CoA + H+
important feature of this step?
The hydrolysis step has a ΔG°ʹ′ = -7.5 kcal/mol. Wasteful?
Acetyl CoA + oxaloacetate + H2O → citrate + CoA + H+
enzyme?
Citrate synthetase
Acetyl CoA + oxaloacetate + H2O → citrate + CoA + H+
rxn type?
condensation/hydrolysis
Citrate —>
with aconitase
cis-aconitate + H2O
Citrate  cis-aconitate + H2O
enzyme?
Aconitase
Citrate —-> cis-aconitate + H2O
rxn type>??
dehydration
cis-Aconitate + H2O —>
with aconitase
isocitrate
cis-Aconitate + H2O —>  isocitrate
rxn type?
hydration
cis-Aconitate + H2O —> isocitrate
eznyme?
acotinase
α-Ketoglutarate + NAD+ + CoA —->
α-Ketoglutarate dehydrogenase complex
succinyl CoA + CO2 + NADH
α-Ketoglutarate + NAD+ + CoA –> succinyl CoA + CO2 + NADH
enzyme?
α-Ketoglutarate dehydrogenase complex
α-Ketoglutarate + NAD+ + CoA –> succinyl CoA + CO2 + NADH
rxn type?
decrboxylation and oxidation
Isocitrate + NAD+ —->
with Isocitrate dehydrogenase
α-Ketoglutarate + CO2 + NADH
isocitrate + NAD+ ——-> α-Ketoglutarate + CO2 + NADH
enzyme?
Isocitrate dehydrogenase
Isocitrate + NAD+ ——-> α-Ketoglutarate + CO2 + NADH
rxn type
oxidation
decarobylation
Succinyl CoA + Pi + GDP –>
with succinyl coa synthetase
succinate + GTP + CoA
Succinyl CoA + Pi + GDP —> succinate + GTP + CoA
enzyme?
succinyl coa synthetase
Succinyl CoA + Pi + GDP —> succinate + GTP + CoA
rxn type?
substrate level phosphorylation
Succinate + FAD (enzyme-bound) –>
fumarate + FADH2 (enzyme-bound)
Succinate + FAD (enzyme-bound) —> fumarate + FADH2 (enzyme-bound)
enzyme?
Succinate dehydrogenase
Succinate + FAD (enzyme-bound) —> fumarate + FADH2 (enzyme-bound)
rxn type
oxidation
Fumarate + H2O –>
malate
Fumarate + H2O —> malate
enzyme?
fumarase
Fumarate + H2O —> malate
reaction type
hydration
Malate + NAD+ –>
oxaloacetate + NADH + H+
Malate + NAD+ —> oxaloacetate + NADH + H+enzyme
malatae dehydrogenase
Malate + NAD+ —> oxaloacetate + NADH + H+enzyme
reaction type
oxidation
Where Coa is produced?
with Citrate and with Succinate
Where is NADH produced?
with a-ketoglutarate
with succinyl COA
with oxaloacetate
