Electron Transport Chain

Question 1

What is the name of complex 1?

Answer 1

NADH-Q oxidoreductase

Question 2

What is the name of complex 2 ?

Answer 2

Succinate-Q reductase

Question 3

What is the name of complex 3?

Answer 3

Q-cytochrome c oxidoreductase

Question 4

What is the name of complex 4?

Answer 4

Cytochrome- c oxidase

Question 5

What does FMN stand for and what do the reduced form carry?

Answer 5

FMN- Flavins

In their reduced form they carry hydrogen( proton plus an electron)

Question 6

What does FeS stand for, what do they carry and what residues are they bound to ?

Answer 6

FeS= iron- sulphur cluster, bound to cysteine residues and carry electrons as they are capable of undergoing oxidation and reduction

Question 7

What is the difference between ubiquinone and ubiquinol?

Answer 7

ubiquinone is the oxidised form of coenzyme Q and ubiquinol is the reduced form of coenzyme Q. They carry electrons and protons.

Question 8

Which out of Q, FMN and FeS can act as a mobile carrier?

Answer 8

Q due to it’s lipophillic nature

Question 9

What is the overall reaction in NADH-Q oxidoreductase?

Answer 9

NADH + Q + 5H+ -> NAD+ + QH2 + 4 H+

Question 10

Q- cytochrome c oxidoreductase is made up of which subunits ?

Answer 10

Riske iron sulphur protein, cytochrome b and cytochrome c1 both cytochromes are to carry hemes. Has heme bL and bH

Question 11

Is cytochrome c covalently or non covalently attached ?

Answer 11

covalently

Cytochrome a and b are non covalently attached.

Question 12

in which complex does the proton motive Q- cycle take place and give a brief description?

Answer 12

in complex 3
one electron goes from Q0- FeS- Cyt c1- Cyt c
and the other goes from Q0-Cyt bL- Cyt bH to Q1

Question 13

what is the overall reaction of complex 3?

Answer 13

Qh2 + 2 cyt c (oxidised + 2 H+ -> Q + 2 Cyt c (reduced) + 4 H+ to cystol

Question 14

Complex 3 leaves you with how many reduced Cyt C’s?

Answer 14

2 Cyt C’s and 1 reduced QH2.

Question 15

Cytochrome c oxidase contains which redox active components?

Answer 15

Heme a, heme a3, and Cua/Cua which is copper and Cub

Question 16

Describe the route of electrons from cytochrome c to CuB.

Answer 16

Cytochrome c- Cua/Cua- Heme a- Heme a3 - CuB

Question 17

What does o2 bind to in cytochrome c oxidase ?

Answer 17

Reduced Fe in heme a3

Question 18

what is the name of the bridge formed from the transfer of electrons to O2?

Answer 18

Peroxide bridge

Question 19

What is the overall reaction of Complex 4?

Answer 19

4 Ctyt C + 4H+ + O2 -> 4Cyt c +2 H2O

Question 20

How many additional protons can complex 4 pump across the membrane?

Answer 20

4 from the matrix the the inter membrane space.

Question 21

The F0 component of ATPase is in the matrix?

Answer 21

No it is located in the membrane and contains a ring of hydrophobic proteins.

Question 22

how many alpha and beta subunits is F1 made up of?

Answer 22

3 alpha and 3 beta

Question 23

which subunit is the catalytic and which is the regulatory in the ATP synthase?

Answer 23

alpha is the regulatory and beta is the catalytic

Question 24

How many subunits does the c ring have in vertebrates and in one rotation how many ATP’s are made?

Answer 24

The c ring contains 8 subunits and in one rotation 3 ATP’s are made

Question 25

what formation does the O, L and T stand for of the alpha and beta subunits of the ATP synthase

Answer 25

0= open and releases ATP
T= tight and L= loose which binds ADP and Pi.

Question 26

what is the P: O ratio for NADH and FADH

Answer 26

NADH- 2.7 and FADH- 1.6.

NADH= 10(protons)/ 3.7( H+ per ATP made) whereas FADH= 6(H+)/ per 3.7( same)