L26 Oxidative Phosphorylation

Question 1

Why do we need O2?

Answer 1

To release energy from NADH and FADH2

Question 2

Energy from electrons is used to drive protons out of the matrix creating a concentration gradient or…

Answer 2

Proton motive force

Question 3

Protons move back into the matrix through…

a) The inner membrane
b) The outer membrane
c) Potassium leak channel
d) ATP synthase

Answer 3

d) ATP synthase

Question 4

The electron transport chain (ETC) contains ? complexes…

Answer 4

4

Question 5

Complex I is…

Answer 5

NADH-Q reductase complex

Question 6

NADH-Q reductase first transfers 2 high energy electrons from…

Answer 6

NADH → FMN

Question 7

NADH-Q reductase transfers electrons from FMNH2 to a series of…

Answer 7

Iron-sulphur clusters

Question 8

In NADH-Q, electrons are transferred from iron-sulphur clusters to…

Answer 8

Coenzyme Q (ubiquinone)

Question 9

Complex III is the…

Answer 9

Cytochrome C Reductase complex

Question 10

Cytochrome C reductase complex transfers how many protons into the intermembrane space?

Answer 10

4

Question 11

NADH-Q reductase transfers how many protons into the intermembrane space?

Answer 11

4

Question 12

In the ETC, electrons:

a) move between matrix and intermembrane space
b) remain within the membrane
c) remain on the matrix side
d) remain on the intermembrane side

Answer 12

b) remain within the membrane

Question 13

Complex IV is the…

Answer 13

Cytochrome C Oxidase complex

Question 14

Cytochrome C Oxidase complex pumps how many protons across the membrane?

Answer 14

4

Question 15

Cytochrome C Oxidase complex uses 4 protons to reduce…

Answer 15

O2 → H2O

Question 16

Cytochrome C Oxidase complex transfers how many electrons to O2?

Answer 16

4

Question 17

In total, how many protons are removed from the matric (net)?

Answer 17

-16

Question 18

In total, how many protons are pumped across to the intermembrane space (net)?

Answer 18

+12

Question 19

In total, how many electrons are added to the membrane (net)?

Answer 19

+4

Question 20

Which substances may cause problems with oxidative phosphorylation (3)…

Answer 20

1. Carbon monoxide
2. Cyanide
3. Salicylate

Question 21

Mitochondrial defects may cause problems with oxidative phosphorylation. These are inherited…

Answer 21

Maternally

Question 22

Salicylate disrupts oxidative phosphorylation by causing…

Answer 22

Pores to form in the mitochondrial membrane. Protons are able to leaks through without passing via ATPase

Question 23

Cyanide disrupts oxidative phosphorylation by…

Answer 23

Binding irreversibly to Complex IV (Cytochrome C oxidase) which blocks oxidative phosphorylation

Question 24

Carbon monoxide disrupts oxidative phosphorylation because it…

Answer 24

Binds irreversibly to haemoglobin, reducing the amount of oxygen available to cells

Question 25

Oxidative phosphorylation takes NADH and FADH2 from glycolysis and the citric acid cycle to generate…

Answer 25

30ATP + 6H2O

Question 26

Electrons flow down the ETC from carrier molecules to O2 by an…

Answer 26

Electron-motive force

Question 27

Uneven distribution of protons generates:

a) pH gradient
b) transmembrane electrical potential
c) Proton-motive force
d) all of the above

Answer 27

d) all of the above

Proton-motive force as a result of the pH gradient and transmembrane electrical potential (more H+ on one side, more +)

Question 28

The ETC protein complexes are located in the…

Answer 28

Mitochondrial inner membrane