Biological Oxidation

Question 1

The outer membrane of mitochondria have pores that make it permeable to small molecules and ions, but not proteins. True or false?

Answer 1

true

Question 2

The inner membrane of a single liver mitochondria may have more than ___ sets of electron-transfer systems and ATP synthase molecules

Answer 2

10K

Question 3

The heart muscle mitochondria contains __ X more electron transfer systems than liver mitochondria

Answer 3

3

Question 4

Muscle and liver mitochondria are about the size of a bacterium __-__ um long

Answer 4

1-2

Question 5

Each complex in the ETC contains multiple ___ centers

Answer 5

redox

Question 6

Coenzyme Q is a mobile electron carrier transporting electrons from complexes ___ and ___ to complex __

Answer 6

1; 2; 3

Question 7

Cytochrome c is the second mobile electron carrier. It carries a single electron from the cytochrome ___ complex to cytochrome ___

Answer 7

bc1; oxidase

Question 8

What is the name for complex I and what does it do?

Answer 8

NADH-UQ oxidoreductase: catalyzes transfer of e- from NADH to UQ or CoQ

Question 9

What is the name for complex II and what does it do?

Answer 9

succinate-ubiquinone oxidoreductase or succinate dh: transfers e- from succinate to CoQ

Question 10

What is the name for complex III and what does it do?

Answer 10

cytochrome bC1 complex: transfers e- from ubiqunol

Question 11

What is the name for complex IV and what does it do?

Answer 11

cytochrome c oxidase: transfers e- from cytochrome c to O2

Question 12

What is the name for Complex V and what does it do?

Answer 12

ATP synthase: uses energy of the electrochemical gradient for synthesis of ATP

Question 13

For the following compound, give its target/mode of action towards inhibiting the ETC:
cyanide, carbon monoxide

Answer 13

inhibit cytochrome oxidase

Question 14

For the following compound, give its target/mode of action towards inhibiting the ETC:
Antimycin A

Answer 14

blocks electron transfer from cytochrome b to cytochrome c

Question 15

For the following compound, give its target/mode of action towards inhibiting the ETC:
myxothiazol, rotenone, amytal, piercidin A

Answer 15

prevent electron transfer from Fe-S center to ubiquinone

Question 16

For the following compound, give its target/mode of action towards inhibiting the ETC:
DCMU

Answer 16

competes with Q for binding site in PSII

Question 17

For the following compound, give its target/mode of action towards inhibition of ATP synthase:
Aurovertin

Answer 17

inhibits F1

Question 18

For the following compound, give its target/mode of action towards inhibition of ATP synthase:
Oligomycin, Venturicidin

Answer 18

inhibits F0 and CF0

Question 19

For the following compound, give its target/mode of action towards inhibition of ATP synthase:
DCCD

Answer 19

blocks proton flow through F0 and CF0

Question 20

For the following compound, give its target/mode of action towards inhibition of ATP-ADP exchange:
atractyloside

Answer 20

inhibits adenine nucleotide translocase

Question 21

Complex I catalyzes the transfer of a hydride ion from ___ to ___, from which 2e- pass through a series of Fe-S centers to the Fe-S center N-2

Answer 21

NADH; FMN

Question 22

Complex I is one of the largest macro-molecular assemblies in the mammalian cell with over ___ different polypeptide chains, encoded by both nuclear and mitochondrial genes

Answer 22

40

Question 23

Succinate DH (complex II) has ABCD subunits. Succinate binds to subunit A just behind the ___

Answer 23

FAD

Question 24

In regards to succinate DH, subunit B has three Fe-S centers, ____ is bound to subunit B, and ___ b is sandwiched between subunits C and D

Answer 24

ubiquinone; heme

Question 25

In reagards to succinate DH, electrons move from succinate to FAD, then through the three Fe-S centers to ubiquinone. FAD accepts ___ electrons from succinate. Electrons pass one at a time via __-__ centers to Q, which becomes reduced QH2

Answer 25

2; Fe-S

Question 26

Does succinate DH (complex II) transport protons?

Answer 26

no

Question 27

In regards to complex III, ubiquinone: cytochrome c oxidoreductase, the complex has two distinct binding sites for ubiquinone, Qn and Qp, which correspond to sites of what?

Answer 27

sites of inhibition by two drugs that block oxidative phosphorylation

Question 28

In regards to complex III, ubiquinone: cytochrome c oxidoreductase, Antimycin A blocks electron flow from ___ __ to ___, binds at ___

Answer 28

heme bh; Q; Qn

Question 29

In regards to complex III, Myxothiazol prevents electron flow from ___ to the ___ __–__ protein, binds at ___

Answer 29

QH2; Rieske iron-sulfur; Qp

Question 30

In regards to complex III, the ___ structure is essential to function. The interface between monomers forms two caverns, each containing a Qp site from one monomer and a Qn site from the other.

Answer 30

dimeric

Question 31

Electron transfer through complex IV begins with cytochrome C, Two molecules of reduced cytochrome c donate an electron to the binuclear center ___

Answer 31

Cua

Question 32

In regards to complex IV, after electrons are donated to Cua, they pass through heme __ to the Fe-Cu center. Delivery of two more electrons from cytochrome c converts the ___ to two molecules of water, with use of 4 substrate protons from the matrix

Answer 32

a; O2

note: at the same time, 4 protons are pumped from the matrix

Question 33

In summary of the ETC, electrons reach Q through complex __ and ___. The reduced Q (___) serves as a mobile carrier of electrons an protons.

Answer 33

I; II; QH2

Question 34

In summary of the ETC, electrons are passed to complex III which passes them to another mobile connecting link, ____ __. Complex IV then transfers electrons from reduced cytochrome C to ___

Answer 34

cytochrome C; O2

Question 35

In summary of the ETC, Complexes I, III, and IV are accompanied by ___ flow from the matrix to the inter membrane space

Answer 35

proton

Question 36

Ubiquinol diffuses freely in the membrane and is oxidized by complex ___

Answer 36

III

Question 37

2 electrons from NADH to O2 result in the translocation of 10 protons across the membrane Thus, for each pair of electrons transferred to O2, there are ___ from complex I, ___ from complex II, and ___ from complex IV

Answer 37

4; 4; 2