Citric Acid Cycle Flashcards

1
Q

T/F citric acid cycle can happen in aerobic and anerobic conditions

A

False , only under aerobic conditions

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2
Q

In which part of the cell does the citric acid cycle take place

A

In the mitochondria

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3
Q

What is the. Name of the substrate that enters the citric acid cycle

A

Acetyl coa

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4
Q

Isocitrate accumulation inhibits what?

A

Isocitrate accumulation inhibits aconitase (enzyme inhibition by the product)

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5
Q

What occurs when there is citrate accumulation in the mitochondria ?

A

Citrate then moves from mitochondria to cytosol
for :
1)Fatty acid synthesis
2)Gluconeogenesis (coz. it inhibits phosphofructokinase,
the rate limiting enz in glycolysis

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6
Q

What are the 2 isoenzymes of of succinyl Coa are specific for which two compounds

A

Two isoenzymes of succinyl-CoA synthetase enzyme:

  1. specific for ADP
  2. specific for GDP [linked to gluconeogenesis; so this one must be present in tissues where gluconeogenesis occurs; e.g. liver, kidney]
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7
Q

What is the name of the enzyme that turns succinate to fumerate?

A

Succinate dehydrogenase

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8
Q

What is the name of the enzyme for the reaction of malate to oxaloacetate

A

Malate dehydrogenase

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9
Q

What are the products formed during one turn on the citric acid cycle

A

3NADH, 1 FADH2, 1 GTP

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10
Q

What happens to the NADH, FADH2 generated in the citric acid cycle

A

Electrons carried by NADH and FADH 2

are funneled into a chain of mitochondrial electrons carriers - the respiratory chain - ultimately reducing O2 to H2O

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11
Q

How many molecules of ATP are generated during the citric acid cycle

A

10

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12
Q

How many water molecules are consumed during the citric acid cycle

A

2

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13
Q

T/F both an ATP and a GTP are formed in the citric acid cycle

A

False! Only one or the other is formed!

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14
Q

NADH is how many ATP

A

2.5

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15
Q

FADH2 is how many ATP

A

1.5

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16
Q

How carbon atoms enter and leave the citric acid cycle

A

2 enter as acetyl coa , 2 leave as co2

17
Q

Is the citric acid cycle :
A) Catabolic
B) Anabolic
C) Amphibolic

A

Amphibolic

18
Q

The citric acid cycle yield _______ power in the form of NADH, FADH2

A

Yields reducing power in the form of NADH ,FADH2

19
Q

T/f : Krebs Cycle is a Source of Biosynthetic Precursors

Glucose

A

Truuuueee

20
Q

You

A

Got this!

21
Q

List the 3 rate controlling enzymes of the citric acid cycle

A

Citrate synthase • Isocitrate dehydrogenase • a-keoglutarate dehydrogenase

22
Q

High cellular conc. of which molecule would inhibit the entry of pyruvate into the citric acid cycle? AMP, Coenzyme A, NADH or Pyruvate?

A

Pyruvate

23
Q

Which substance is a product of glycolysis, a precursor of gluconeogenesis and a precursor of the TCA cycle? Glucose, Pyruvate, ATP, or CoA?

A

Pyruvate