Lecture3-ETC AND OXIDATIVE PHOSPHORYLATION

Question 1

Why do we need mitochondria?

Answer 1

1.ATP biosynthesis
2. Mediation of cell death by apoptosis
3. Heat production (thermogenesis)
4. Intermediary metabolism (e.g. TCA cycle, fatty acid metabolism)
5. Genetics (maternal inheritance)

Question 2

What is the function of the ETC?

Answer 2

Produce ATP through respiratory chains that produce a proton gradient

Question 3

Where is the ETC being taken place?

Answer 3

Mitochondria intermembrane space and inner mitochondrial membrane

Question 4

What is the NET energy of ETC

Answer 4

9 from NADH, 2 more FADH2 and I from GTP per TCA cycle

Question 5

Which complexes make ATP?

Answer 5

I, III, IV

Question 6

Which complex does not go through the membrane nor produce ATP?

Answer 6

Complex II

Question 7

What is used in Complex I to work?

Answer 7

NADH dehydrogenase
FMN
Fe-S centers

Question 8

What is used in Complex III to work?

Answer 8

Cytochrome bc1 complex
2b-type heme centers
riseske Fe-S center
o-type heme (cyt c1)

Question 9

What does Complex II use to work?

Answer 9

Succinate dehydrogenase
FAD (covalent)
Fe-S centers
b-type heme

Question 10

What is used in complex IV to work?

Answer 10

Cytochrome aa3 complex
2 a-type hemes
Cu ions

Question 11

Which complexes use Fe-S centers?

Answer 11

I,II,III

Question 12

Which complexes use heme groups?

Answer 12

II,III,IV

Question 13

Which complex uses Cu ions ?

Answer 13

IV

Question 14

Which complex use NADH?

Answer 14

Complex I with NADH dehydrogenase

Question 15

What complex uses FADH2?

Answer 15

Complex II with succinate dehydrogenase

Question 16

What complex is the cytochrome b-c1 complex?

Answer 16

III

Question 17

What complex is the cytochrome c oxidase?

Answer 17

IV

Question 18

Where do the electrons end?

Answer 18

Cyt c

Question 19

What is Q

Answer 19

Q acts as a mobile component of the respiratory chain that collects reducing equivalents from the more fixed flavoprotein complexes and passes them on to the cytochromes.

Question 20

Hydrogens get move from ____ to _____

Answer 20

matrix to intermembrane space

Question 21

What P/O ratio?

Answer 21

number of energy-rich phosphate groups formed as ATP per oxygen molecule reduced in mitochondria

Question 22

What is the p/o ratio go nadh?

Answer 22

3

Question 23

What is the p/o ratio of Succinate/Fadh2?

Answer 23

2

Question 24

What inhibits Complex I?

Answer 24

Rotenone= broad spectrum insecticide

Question 25

what inhibits complex III?

Answer 25

antimycin A = antibiotic

Question 26

What inhibits complex IV?

Answer 26

cyanide and carbon monoxide = poison

Question 27

Besides blocking the complexes, what can inhibit ETC?

Answer 27

Iron deficiency anemia – cytochromes and sulfur-iron complexes of oxidative phosphorylation

Question 28

Oxidation of substrates is coupled to what?

Answer 28

phosphorylation of ADP -> ATP -> O2 consumption

Question 29

Respiration can only proceed when_____

Answer 29

Respiration (consumption of oxygen) proceeds only when ADP is present

Question 30

What is chemiosmotic theory?

Answer 30

This hypothesis states that a proton-motive force is responsible for driving the synthesis of ATP

Question 31

What are the 4 tenets of Chemiosmotic theory?

Answer 31

-Inner mitochondrial membrane is impermeable to protons -Protons are pumped vectorially across inner mitochondrial membrane -Electron transport and ATP synthesis are tightly coupled -Presence of an ATP synthase

Question 32

What part of the ATP synthase is within the matrix?

Answer 32

F1

Question 33

What part of the ATP synthase is within the inner mitochondrial membrane?

Answer 33

F0

Question 34

what is the purpose of ATP synthase?

Answer 34

to make ATP

Question 35

What is the major source for mitochondrial ROS production

Answer 35

Complex III

Question 36

Coenzyme Q makes what

Answer 36

unstable intermediates of the Q cycle (*Q -) can lead to superoxide (H2O2) formation

Question 37

What is the protection against ROS and harmful oxidative stress

Answer 37

Superoxide dismutase (SOD) and catalase

Question 38

Where do mitochondrial disease come from?

Answer 38

Maternal inheritance

Question 39

The ETC is a source of what (not good)

Answer 39

ROS as a side product or electron leakage

Question 40

What is the p/o ratio of Succinate/Fadh2?

Answer 40

2