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57 terms

TCA Cycle

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What is another name for the TCA cycle?
citric acid cycle
When did oxidative phosphorylation evolve?
1-2 billion years ago
Why did oxidative phosphorylation evolve?
O2 became plentiful
What is the purpose of the TCA cycle?
to extract energy from pyruvate
What is unique about the intermediate step that converts pyruvate into acetyl-CoA?
It is the final common pathway for the oxidation of fuel molecules.
Where does the intermediate step that converts pyruvate into acetyl-CoA occur in eukaryotes?
mitochondria
Where does the intermediate step that converts pyruvate into acetyl-CoA occur in aerobic bacteria?
cytosolic membrane
Where does the intermediate step that converts pyruvate into acetyl-CoA occur in anerobic bacteria?
It dosen't occur.
What is produced by the intermediate step that converts pyruvate into acetyl-CoA?
acetyl-CoA + CO2 + NADH
What is used by the intermediate step that converts pyruvate into acetyl-CoA?
pyruvate + CoA + NAD+
What is the net reaction of the intermediate step that converts pyruvate into acetyl-CoA?
pyruvate +CoA + NAD+ -> acetyl-CoA + CO2 + NADH
What two process does the intermediate step that converts pyruvate into acetyl-CoA?
glycolysis and the TCA cycle
Where in the mitochondria does the formation of acetyl-CoA from pyruvate occur?
matrix
What type of reaction is the one that converts pyruvate into acetyl-CoA?
oxidative decarboxylation
What enzymes are used to form acetyl-CoA from pyruvate?
pyruvate dehydrogenase complex
Tell me about the pyruvate dehydrogenase complex.
It is a multi-enzyme complex.
How many enzymes does the pyruvate dehydrogenase complex contain?
3
What is the purpose of forming enzyme complex?
The close proximity of the enzymes increase the overall rate of reaction and decreases side reaction.
What coenzyme is necessary for the formation of the pyruvate dehydrogenase complex?
thiamine
What is vitamin B1?
thiamine
What is thiamine?
vitamin B1
What is a deficiency of thiamine called?
beriberi
What is beriberi?
a deficiency of thiamine
What does the pyruvate dehydrogenase complex require thiamine?
Thiamine is used to form cofactor TPP.
What is TPP used for?
the pyruvate dehydrogenase complex
What is beriberi characterized by?
increase blood pyruvate and alpha-ketoglutarate levels
Which is more reduced CO2 or an acetyl group?
acetyl group
What type of reactions are the most common in the TCA cycle?
redox
When is oxaloacetate used?
in the TCA cycle
How many NADH are produced by the TCA cycle?
3
How many FAD are produced?
1
What is FAD reduced to?
FADH2
What is NADP+ reduced to?
NADPH
What is NAD+ reduced to?
NADH
When FAD becomes FADH2 is oxidized or reduced?
reduced
Alpha-ketoglutarate is found in what step?
TCA cycle
What are the reactants of the TCA cycle?
acetyl-CoA + GDP + Pi + FAD + 3NAD+
What are the products of the TCA cycle?
2CO2 + 3NADH + FADH2 + GTP + CoA + 2H+
What is the net reaction of the TCA cycle?
acetyl-CoA + GDP + Pi + FAD + 3NAD+ -> 2CO2 + 3NADH + FADH2 + GTP + CoA + 2H+
NADH can be used to generate how many ATP?
3
FADH2 can be used to generate how many ATP?
2
Where is O2 used in the cell?
mitochondria
What is the average length and width of a mitochondria?
1-4 micrometers in length and 0.2-1 micrometers in width
Where do we believe mitochondria and chloroplast come from?
a symbiotic relationship between the cell and a bacteria
Do different cells have different number of mitochondria normally?
yes
How many mitochondria are found in liver cells?
~1500
What percent of the volume of a liver cell is the mitochondria?
20-30%
How do the number of mitochondria in liver cells compare to that of the skeletal muscle cells?
Skeletal muscle cells have more mitochondria then liver cells.
How many membranes are found around a mitochondria?
2
What are the names of the membranes?
outer membrane and inner membrane
What is another name for cristae?
inner membrane
What is the purpose of the outer membrane?
It encases organelle.
Describe the inner membrane?
It is highly folded.
What is the purpose of the inner membrane?
It divides the interior into two aqueous compartments.
What is the inner compartment called?
matrix
What is the matrix?
It is the inner compartment of the mitochondria.
What is the intramembranous space?
the outer compartment of the mitochondria