lecture 30 - the final oxidation : the citric acid cycle Flashcards

1
Q

where does the citric acid cycle occur

A

in the mitochondrial matrix

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2
Q

where does B oxidation occur

A

in the mitochondrial matrix

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3
Q

where does the electron transport chain occur

A

in the inner membrane

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4
Q

what enters and leaves the citric acid cycle

A

2 C enters as acetyl-CoA

2 C out as 2 x CO2 (oxidation complete)

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5
Q

what energy is captured from the citric acid cycle

A

1 ATP
3 NADH and 1 FADH2

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6
Q

what reactions produce acetyl-CoA for the citric acid cycle

A

glycolysis (aerobic, PHD reaction) and B oxidation

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7
Q

what are the two stages of the citric acid cycle

A
  1. release of C
  2. regeneration of the starting molecule
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8
Q

where does the energy come from to attach acetyl-CoA to 4 oxaloacetate to produce 6 C citrate

A

hydrolysis of CoA from acetyl-CoA

energetically favourable = the energy to add the two carbons is from coming from taking the CoA off

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9
Q

in the citric acid cycle what does the rearrangement of citrate to isocitrate make the molecule susceptible

A

decarboxylation

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10
Q

what are the consequences of inhibiting the citric acid cycle

A
  • increased acetyl-CoA
  • decreased reduced enzyme
  • less ATP
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11
Q

what type of reaction is removal of the first carbon in the citric acid cycle and how many steps are involved, what form is energy captured in

A

oxidative decarboxylation, 2 steps

energy captured = NADH

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12
Q

what type of reaction is the removal of the second carbon in the citric acid cycle and what reaction is it similar to

A

a second oxidative decarboxylation reaction

  • very similar to the pyruvate dehydrogenase reaction
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13
Q

how many carbons are removed in total from the citric acid cycle

A

2 carbons removed

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14
Q

what is the second phase of the citric acid doing

A

regenerating oxaloacetate and capturing more energy

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15
Q

what is GTP the energy equivalent of

A

ATP

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16
Q

what is substrate level phosphorylation

A

the direct use of energy from a substrate molecule to drive the synthesis of ATP (or equivalent like GTP)

  • occurs in glycolysis and also turning succinyl-CoA to succinate
17
Q

in the citric acid cycle the succinate to fumarate loses two hydrogens meaning it is a …. reaction

A

oxidation reaction

18
Q

what enzyme in the citric acid cycle sits in the mitochondrial matrix

A

succinate dehydrogenase enzyme

19
Q

why is succinate dehydrogenase enzyme found in the inner mitochondrial membrane

A

because it is a part of the citric acid cycle where FAD is reduced

  • also needs to be in the electron transport chain to oxidise FADH2 back to FAD
20
Q
A