Electron Transport Chain

Question 1

What is the main point regarding the electron transport chain?

Answer 1

The transport of electrons from NADH to O2 is a multi-step process and coupled to ATP formation (oxidative phosphorylation)

Question 2

Inside the inner mitochondrial membrane, what is the environment like?

Answer 2

high pH (basic)
low [H+]

Question 3

In the inner membrane space (between the inner mitochondrial membrane and the outer mitochondrial membrane), what is the environment like?

Answer 3

low pH (acidic)
high [H+]

Question 4

What are the cofactors at complex 1?

Answer 4

NADH + H+ —> NAD+

Question 5

How many protons cross the IMM at complex 1?

Answer 5

4 H+

Question 6

What are the cofactors at complex 2?

Answer 6

• succinate is converted to fumarate

- FAD is converted into FADH2

Question 7

How many protons cross the IMM at complex 2?

Answer 7

none

Question 8

What are the cofactors at complex 3?

Answer 8

Well electrons from UQH2 –> UQ get transported through complex 3 and then head to cytochrome c and then enter complex 4

Question 9

How many protons cross the IMM at complex 3?

Answer 9

4 H+

Question 10

What are the cofactors at complex 4?

Answer 10

1/2O2 + 2H+ –> H20

Question 11

How many protons cross the IMM at complex 4?

Answer 11

2 H+

Question 12

Next there is ATP synthesis driven by proton-motive force which transports the 10H+ from the inter membrane space into the matrix. How many ATP molecules are produced?

Answer 12

2.5 ATP

4H+/ATP

Question 13

Next there is ATP synthesis driven by proton-motive force which transports the 10H+ from the inter membrane space into the matrix. What co factors drive this pump?

Answer 13

ADP + Pi –> ATP

Question 14

What conditions drive the ATP synthesis?

Answer 14

• chemical potential inside is alkaline

- electric potential inside is negative

Question 15

What formula is associated with ETC?

Answer 15

deltaG = -nFdeltaE’°

Question 16

What does NAD stand for?

Answer 16

Nicotinamide Adenine Dinucleotide

Question 17

How does electrons flow through the ETC?

Answer 17

Carriers with high negative reduction potentials (E’°) pass electrons to carries with high positive reduction potentials.

Question 18

Describe complex 1

Answer 18

NADH dehydrogenase, FMN flavoprotein + FeS, CoQ (ubiquinone)

Question 19

Describe complex 2

Answer 19

Succinate dehydrogenase

Question 20

Describe complex 3

Answer 20

cytochrome b + c1 + 11 proteins

Question 21

Describe complex 4

Answer 21

cytochrome oxidase (a + a3 + 13 proteins)

Question 22

Describe the transfer of electrons in complex 1

Answer 22

NADH to CoQ

Question 23

Describe the transfer of electrons in complex 2

Answer 23

succinate dehydrogenase with FAD transfers e- to CoQ

Question 24

Describe the transfer of electrons in complex 3

Answer 24

CoQ to cyt c

Question 25

Describe the transfer of electrons in complex 4

Answer 25

cyt c to O2

Question 26

What is the deltaE’° for ETC

Answer 26

+1.14 volts

Question 27

What is the deltaG’° for ETC

Answer 27

-220 kJ/mol

Question 28

After glycolysis how many ATP are made?

Answer 28

7

Question 29

After pyruvate to acetyl CoA how many ATP are made?

Answer 29

5 (plus 7 from glycolysis gives a total of 12)

Question 30

How many ATP are made from the citric acid cycle?

Answer 30

20 (plus 12 is a total of 32)

Question 31

How many ATP total from glycolysis and TCA?

Answer 31

32 ATP

Question 32

How much energy is in 1 ATP molecule?

Answer 32

976 kJ/mol (34% of 2840kJ/mol available) so that suggests that 65% of the G is conserved