KREBS CYCLE!!! Flashcards

1
Q

Where does the citric acid cycle occur?

A

Mitochondrial matrix

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2
Q

What does CAC accomplish for the cell?

A

Tranfers 8 electrons froma acetyl CoA to reduce NAD+ and FAD to form 3NADH and 1FADH2 that are later oxidized to produce ATP. Also produces 1 GTP by SLP and 2CO2 as waste

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3
Q

What is the overall net reaction

A

Acetyl CoA + 2NAD+ + FAD+ + GDP +Pi + 2H2O –> CoA + 2CO2 + 3NADH + 3H+ = FADH2 + GTP(ATP)

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4
Q

What are the key enzymes in the CAC

A

pyruvate dehydrogenase, citrate cynthase, isocintrate dehydrogenase, alpha-ketoglutarate dehydrogenase

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5
Q

What is an example in everyday biochemistry?

A

Fluroacetate disrupts the CAC in plants by binding to coenzyme A

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6
Q

What does pyruvate dehydrogenase do?

A

Converts pyruvate to acetyl coA

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7
Q

What are the five coenzymes the pyruvate dehydrogenase complex needs?

A
-NAD+
FAD
CoA
TPP
lipoamide
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8
Q

What are the four vitamins required to synthesize the coenzymes

A
Vitamin B3 (NAD+)
Vitamin B2 (FAD)
Pantothenic acid (CoA)
B1 (Thiamine)
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9
Q

FAD and FMN can only transfer __ electron at a time to be come partially reduced to ______

A

one, semiquinone

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10
Q

What are the two fates of acetyl-coA

A

can be metabolized to ATP or used to store energy as fatty acids

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11
Q

What are the products after one turn of the CAC

A

3NADH
FADH2
GTP
2CO2 (waste)

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12
Q

What is teh net reaction for CAC 1

A

Acetyl CoA + Oxaloacetate + H2O –> (Citrate synthease) CoA + Citrate

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13
Q

What is teh net reaction for rxn 3

A

Isocitrate + NAD+ —> (Isocitrate dehydrogenase) alpha ketoglutarate + NADH + CO2 + H+

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14
Q

What is the net reaction for rxn 4

A

alpha-ketoglutarate + CoA + NAD+ –> (alpha-ketoglutarate dehydrogenase) Cuccinyl - CoA + NADH + CO2 + H+

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15
Q

What are the three factors that regulate the CAC

A

substrate availability
inhibition by accumulating products
allosteric feedback inhibition that catalyze early steps in the cycle

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16
Q

What is is the net equation of the pyruvate dehydrogenase complex

A

pyruvate + CoA + NAD+ –> acetyl- CoA + CO2 + NADH + h+

17
Q

IN the pyruvate dehydrogenase complex, what is the E1, E2 and E3 substrates?

A

E1- TPP
E2- lipoamide
E3- FAD