1.9 Citric Acid Cycle Flashcards Preview

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Flashcards in 1.9 Citric Acid Cycle Deck (32):
0

When is Pyruvate Dehydrogenase ACTIVE?

When it is dephosphorylated

1

What is an anaplerotic reaction

when intermediates of the citric acid cycle need to be replenished if they are diminished

2

What four molecules speed up the reaction of Pyruvate Dehydrogenase

AMP, CoA, NAD+ and Ca2+

3

How does pyruvate get into mitochondria?

It diffuses through the outer membrane through Porins

4

How does pyruvate enter the matrix of mitochondria

Pyruvate translocase

5

Where is pyruvate translocase located and what is its function?

It is embedded in the inner membrane of mitochondria
It transports pyruvate into the matrix of mitochondria

6

What is the link between glycolysis and citric acid cycle

Oxidative decarboxylation of pyruvate to acetyl CoA (pyruvate dehydrogenase complex)

7

What are the products of the pyruvate to Acetyl CoA reaction?

Acetyl CoA
CO2
NADH

8

Is the pyruvate to Acetyl CoA reaction reversible?

No, the high negative delta G makes the reaction hard to reverse. It is practically irreversible

9

How many enzymes are involved in the Pyruvate Dehydrogenase complex? What are they?

1. Pyruvate Dehydrogenase
2. Dihydrolipoyl Transacetylase
3. Dihydrolipoyl Dehydrogenase

10

What are the 5 coenzymes of the pyruvate dehydrogenase complex

1. Thiamine
2. Riboflavin
3. Niacin
4. Pentothanate
5. Lipoate (Lipoic Acid)

11

Name the 4 vitamin precursors of the 5 coenzymes of pyruvate dehydrogenase complex

1. B1 (Thiamine)
2. B2 (Riboflavin)
3. B3 (Niacin)
4. B5 (Pentothenate)

12

Acetyl group is activated by formation of what?

high energy thioester bond

13

Where does the citric acid cycle take place?

Mitochondrial matrix

14

How many CO2 are released during one turn of the citric acid cycle

2 CO2 are released during the citric acid cycle

15

How many redox reactions are found in the citric acid cycle

4

16

How many NADH and FADH2 are released in the Citric Acid cycle

3 NADH and 1 FADH2

17

How many high energy phosphate bonds are made during citric acid cycle

1 GTP (can be turned into ATP)

18

For one molecule of Glucose, how many CO2 are produced through glycolysis through citric acid cycle

6 -->
2, 1 per pyruvate in pyruvate to acetyl CoA
4, 2 per pyruvate in citric acid cycle

19

How many NAD+ molecule are reduced to NADH for one glucose throughout citric acid cycle

10
2, Glycolysis
2, 1 per pyruvate in pyruvate to acetyl CoA
6, 3 per pyruvate in citric acid cycle

20

Theoretically, how many ATP are possible through oxidation of one glucose molecule

32

21

What four reactions control the Citric Acid cycle

1. Pyruvate Dehydrogenase complex
2. Citrate Synthase
3. Isocitrate Dehydrogenase
4. alpha-Ketoglutarate Dehydrogenase

22

What four things slow down the conversion of acetyl CoA to Citrate through Citrate Synthase

1. ATP
2. Acetyl CoA
3. NADH
4. Succinyl CoA

23

What two things Slow Down the Isocitrate Dehydrogenase reaction

1. ATP
2. NADH

24

What speeds up the isocitrate dehydrogenase reaction?

ADP

25

What four things slow down alpha-ketoglutarate dehydrogenase reaction

1. ATP
2. GTP
3. NADH
4. Succinyl CoA

26

What three steps of the Citric Acid Cycle are regulatory and considered Strongly Exergonic steps

1. Citrate Synthase
2. Isocitrate Dehydrogenase
3. Alpha-Ketoglutarate Dehydrogenase

27

What two main molecules inhibit the regulatory steps of citric acid cycle

ATP and NADH

28

What five things allosterically inhibit pyruvate dehydrogenase reaction

1. ATP
2. NADH
3. GTP
4. Acetyl CoA
5. Long chain fatty acids

29

Which four things activate pyruvate dehydrogenase reaction

1. AMP
2. CoA
3. NAD+
4. Ca2+

30

What regulation is faster in regard to the citric acid cycle and pyruvate dehydrogenase reaction, Allosteric or Covalent

Allosteric

31

Other than ATP and NADH, what regulates Glycolysis and Citric Acid Cycle

The concentration of Citrate regulates PFK1