Exam 2 Lecture 20 OxPhos

Question 1

What are the 2 membrane systems of the mitochondria

Answer 1

Outer and inner membrane

Question 2

Why is the outer membrane permeable?

Answer 2

Presence of porin aka voltage dependent anion channel VDAC

Question 3

Why is the inner membrane impermeable

Answer 3

Has metabolite transporters; very selective NADH and FADH2 are polar and use special transport

Question 4

What are the 2 compartments of the mitochondria

Answer 4

Intermembrane space and matrix

Question 5

Matrix of mitochondria is site of

Answer 5

TCA cycle and fatty acid oxidation

Question 6

Ox Phos occurs where

Answer 6

In inner membrane

Question 7

TCA cycle generates NADH and FADH2 which, in Ox Phos, flow through

Answer 7

4 protein complexes called the ETC

Question 8

E-s reduce molecular O2 to

Answer 8

H20

Question 9

Protons return to matrix by flowing through another complex called

Answer 9

ATP synthase

Question 10

What is the mission of Ox Phos

Answer 10

1. To transfer e-s from NADH and FADH2 to O2
2. To establish proton gradient across the inner mito membrane
3. To synthesize ATP

Question 11

Electron flow is exergonic or endogonic?

Answer 11

Exergonic

Question 12

Succinate Q reductase mechanism

Answer 12

Does not produce protons but moves protons from one complex to another

Question 13

Succinate Q reductase has succinate dehydrogenase which

Answer 13

Generates FADH2 in TCA cycle

Question 14

Complex I, III, and IV called

Answer 14

Respirasome

Question 15

What are the 3 complexes that shuttle e-s from NADH to O2?

Answer 15

1. NADH Q oxidoreducatase (complex I)
2. Q cytochrome c oxidoreductase (complex III)
3. Cyctochrome c oxidase (complex IV)

Question 16

What are the 2 mobile e- carriers? Ie helpers?

Answer 16

1. Coenzyme Q aka ubiquinone

2. Cytochrome c

Question 17

Mechanism of coenzyme Q

Answer 17

Transfers e-s from NADH Q oxidoreductase and the Succinate Q reductase to Q cytochrome c oxidoreductase

E-s from complex I and II and transfers to complex III

Question 18

What makes coenzyme Q hydrophobic

Answer 18

Long tail made of 5 - C isoprene units

Question 19

Mechanism of cytochrome c

Answer 19

Shuttles e-s from Q cytochrome c oxidoreductase to cytochrome c oxidase

Ie shuttles e-s from complex complex III to complex IV

Question 20

Cytochrome catalyzes _

Answer 20

Reduction of O2

Question 21

What is the first point of entry of e-s from NADH

Answer 21

Complex I aka NADH dehydrogenase aka NADH-Q oxidoreductase

Question 22

Complex I is encoded by both _ and _ genes

Answer 22

Nuclear and mitochondrial genes

Question 23

Iron sulfur clusters undergo what reaction?

Answer 23

Redox; donates e-s

Question 24

Do protons leave iron sulfur clusters present in iron sulfur proteins?

Answer 24

No

Question 25

FADH2 enters the ETC through

Answer 25

Complex II aka succinate-Q reductase

Question 26

Complex II connects _ to Oxphos (succinate dehydroenase)

Answer 26

TCA

Question 27

Which complexes produce protons?

Answer 27

Complex I, III, and IV

Question 28

Does FADH2 leave complex II?

Answer 28

No, donates e-s; e-s will be moving foward not FADH2 * e-s -> FeS -> Q to from QH2 *

Question 29

What is occurring in Complex III?

Answer 29

E-s from QH2 (complex II) are passed on to cytochrome c via complex III. Flow of e-s through complex III leads to transport of 2 protons to cytoplasmic side

Question 30

What is happening in Complex IV, the final stage of the ETC cascade?

Answer 30

4 e-s are funned to O2 (final acceptor) to reduce it to H20. Concomitantly, protons are pumped from matrix to cytoplasmic side of inner membrane

Question 31

What is the 1 job of Cytochrome c Oxidase and what is it made of (structurally)?

Answer 31

One job is to transfer e-s; made of 2 heme and 3 Cu

Question 32

Free radical is a toxic derivative of _

Answer 32

Oxygen

Question 33

How are reactive oxygen species (ROS) formed?

Answer 33

By partial reduction of O2

Question 34

ROS include:

Answer 34

- superoxide ion - peroxide ion - hydroxyl radical

Question 35

Mitochondria are a result of an _ event

Answer 35

An endosymbiotic event is thought to have occurred whereby a free-living organism capable of oxidative phosphorylation was engulfed by another cell.

Question 36

Superoxide dismutase (SOD) functions to do what?

Answer 36

cellular defense strategy that scavenges superoxide radicals by catalyzing the conversion of two of these radicals into hydrogen peroxide and molecular oxygen

Question 37

what is the function of catalse

Answer 37

takes the hydrogen peroxide formed from SOD and catalyzes the dismutation of hydrogen peroxide into water and molecular oxygen

Question 38

Glutathione peroxidase functions to

Answer 38

cellular defense as it scavenges hydrogen peroxide

Question 39

T/F: Vit E and C are other cellular defenses against oxidative damage

Answer 39

true. Vit E is lipophilic so is useful in protecting membranes from lipid peroxidation

Question 40

Eukaryotes contain 2 forms of SOD, which are:

Answer 40

- Mn/Zn SOD present in mitochondria | - Cu/Zn SOD dependent cytoplasmic form

Question 41

transfer of a _ e- to O2 forms superoxide ion, whereas the transfer of _ e- yields peroxide

Answer 41

transfer of 1 e- = superoxide and transfer of 2 e-s = peroxide

Question 42

Glucose + 10NAD+ + 2FAD + 2(ADP + Pi) + 2 (GDP + Pi) ->

Answer 42

6CO2 + 10(NADH + H+) + 2FADH2 + 2ATP + 2GTP THE OXIDATION OF FUELS (phase 1 of respiration) ``` 10 NADH = 25 ATP (2.5 per H+) 2 FADH = 3 ATP (1.5 per H+) 2 GTP = 2 ATP 2 ATP = 2 ATP NET TOTAL = 32 ATP ```