citric acid cycle and respiratory chain

Question 1

Outline the citric acid cycle

Answer 1

Question 2

What are the other names for the citric acid cycle?

Answer 2

• Krebs cycle
• Tricarboxcylic acid cycle

Question 3

Where does the citric acid cycle take place?

Answer 3

In the matrix of the mitochondria

Question 4

What is FAD?

Answer 4

• Flavin adenine dinucleotide
• Formed from vitamin riboflavin (vitamin B2)

Question 5

What is caused by deficiency of vitamin riboflavin?

Answer 5

• Lesions of the mucous membranes:
• Cracked, sore lips and corners of the mouth
• Similar in genital regions
• Tongue swollen, tender and magenta

Question 6

Describe the translocation and decarboxylation of pyruvate

Answer 6

• Moves from the cytoplasm to the matrix of the mitochondria
• Combines with CoA
• Donates to NAD+, converting it to NADH
• Gives off a CO2 molecule
• Produces Acetyl Co A which becomes the acyl unit and CoA

Question 7

Which vitamin is contained in CoA?

Answer 7

Vitamin B5: Pantothenic acid

Question 8

Where does the repiratory chain happen?

Answer 8

Macromolecular assemblies in the inner mitochondrial membrane

Question 9

What are the complexes in the respiratory chain?

Answer 9

• Complex I: NADH cytochrome Q reductase
• Complex II: Succinate coenzyme Q oxidoreductase
• Complex III: Cytochrome reductase
• Complex IV: Cytochrome C oxidase

Question 10

Where does NADH feed into the respiratory chain?

Answer 10

To complex I (NADH cytochrome Q reductase)

Question 11

Where does FADH2 feed into the respiratory chain?

Answer 11

(in flavoproteins ) To complex II (succinate coenzyme Q oxidoreductase)

Question 12

Which of the complexes in the respiratory chain can generate proton gradients?

Answer 12

Complex I and complex II

Question 13

Which of the complexes is lipid solubule?

Answer 13

Complex II (succinate coenzyme Q oxidoreductase)

Question 14

How many proteins are present in complex II?

Answer 14

4

Question 15

Describe electron transfers at complex II

Answer 15

It can undergo 1 or 2 electron transfers

2= ubiquinone

1= semiquinone

Question 16

How many proteins are present in complex I?

Answer 16

34

NADH cytochrome C reductase

Question 17

How many proteins are present in Cyctochrome Reductase?

Answer 17

10

Question 18

Where is the proton concentration highest in the mitochondria?

Answer 18

In the intermembrane space

Question 19

What is used to drive ATP synthesis?

Answer 19

Caused by the movement of e- down the electron chain which generates a H+ ion (pH) gradient across the inner mitochondrial membrane

Question 20

How many molecules of ATP are generated from one NADH molecule?

Answer 20

3

Question 21

How many molecules of ATP are generated from one molecule of FADH2

Answer 21

2

Question 22

How many molecules of ATP are made in glycolysis and what is the net amount?

Answer 22

Makes 4 ATP and the net amount is 2

Question 23

How many molecules of ATP are made per molecule of glucose (net)

Answer 23

4

Question 24

Describe the number of ATP made after mitochondrial oxidative phosphorylation

Answer 24

• 4 from ATP production
• 3-5 ATP from the 2 cytoplasmic NADH
• 20 ATP from the 8 mitochondrial NADH
• 3 ATP from the 2 FADH2

Total = 30-32 ATP

Question 25

Which chemical agents are targets for the respiratory chain?

Answer 25

• Rotenone- insecticide, piscicide
• Antimycin A - Antibiotic
• Cyanide and carbon monoxide block the final step by which hydrogen combines with oxygen