L8 Oxidative phosphorylation

Question 1

What is the function of NADH dehydrogenase (Complex one)?

Answer 1

Transferring electrons from NADH to unbound ubiquinone (Q) to form ubiquinol (QH2)

Question 2

Each Fe is always coordinated by how many S in the Iron-sulfur clusters?

Answer 2

Four

Question 3

What is the function of Succinate dehydrogenase (Complex two)?

Answer 3

Transferring succinate to fumarate

Question 4

Is there any proton pumping in Complex two?

Answer 4

No

Question 5

Which complex is the only membrane -bound enzyme in TCA cycle?

Answer 5

Complex 2

Question 6

What is the function of Cytochrome oxidase (Complex four)?

Answer 6

Transfers electrons from cytochrome c to oxygen

Question 7

For every 2 electrons donated by NADH, how many ATPs are synthesized?

Answer 7

2.5

Question 8

For every 2 electrons donated by FADH2, how many ATPs are synthesized?

Answer 8

1.5

Question 9

How many electrons NAD+/NADH and NADP+/NADPH carries at a time?

Answer 9

2

Question 10

Is NAD+/NADH and NADP+/NADPH diffusible or bound in enzymes?

Answer 10

Diffusible

Question 11

Is FAD/FADH2 and FMN/FMNH2 diffusible or bound in enzymes?

Answer 11

Bound in enzymes

Question 12

What is the highly folded inner membrane called?

Answer 12

Cristae

Question 13

Where does the electron flow occur?

Answer 13

The inner membran of mitocondria

Question 14

The energy released form the electron transference is used for what process in complex one?

Answer 14

Proton pumping from the matrix ito intermembrane space

Question 14

What is the initial electron donor?

Answer 14

NADH

Question 15

How many electron and proton can FMN transfer at a time?

Answer 15

1

Question 16

What is the final eletron carrier in complex one?

Answer 16

Q/QH2

Question 17

Are they any energy release in Complex two?

Answer 17

Yes, but really little (-2kJ /mol), not enough to pump the proton

Question 18

What are the electron carriers in Complex three?

Answer 18

(1) Fe-S clusters
(2) Cytochrome b
(3) Cytochrome c1

Question 19

Is cytochrom c water soluble?

Answer 19

Yes

Question 20

How many protons do complex two pumps per
2 electrons transferred?

Answer 20

4

Question 21

What is the main result of the first round in the Q cycle?

Answer 21

QH2 becomes a half-reduced semiquinon (.Q-)

Question 22

WHat are the electron carriers in Complex four?

Answer 22

2 Cu ions and 2 heme A groups (cytochrome a proteins)

Question 23

In which Complex Oxygen is used up and water is generated?

Answer 23

Complex 4

Question 24

Oxygen oxidized which molecule in Complex four?

Answer 24

cytochrome c

Question 25

How many proton does Complex four pumped out?

Answer 25

2 protons per 2 electrons

Question 26

The energy stored in the gradient, proton-motive force, has two components, what are they?

Answer 26

(1) Chemical potential energy (inside alkaline)
(2) Electrical potential energy (inside negative)

Question 27

What are the two units of ATP synthase?

Answer 27

F0 and F1

Question 28

Protons flow through which unit of ATP synthase?

Answer 28

F0

Question 29

ATP is synthesized by which unit?

Answer 29

F1

Question 30

Why NADH need to have a shuttle system?

Answer 30

Because inner mitochondrial membrane is impermeable to NADH

Question 31

What are the two different shuttle system for NADH?

Answer 31

(1) Glycerol 3-P shuttle system
(2) Malate-aspartate shuttle