Cell Integrity

Question 1

Where does OxPhos take place within the mitochondrium?

Answer 1

Inner membrane, through ETC

Question 2

How many complexes are found in ETC?

Answer 2

4 Complexes + 2 Mobile Carriers

Question 3

What is the name of Complex I?

Answer 3

NADH Dehydrogenase

Question 4

What is the name of Complex II?

Answer 4

Succinate dehydrogenase

Question 5

What is the name of Complex III?

Answer 5

Q-cytochrome C oxireductase

Question 6

What is the name of Complex IV?

Answer 6

Cytochrome C Oxidase

Question 7

What are the mobile carriers of ETC?

Answer 7

Coenzyme Q (Ubiquinone)
Cytochrome C

Question 8

What is the role of oxygen in OxPhos?

Answer 8

Last electron acceptor - oxidise NADH and FADH2

Question 9

Which complexes in ETC pump protons from the matrix into the intermembrane space?

Answer 9

Complexes I, III and IV

Question 10

Which complexes do NADH and FADH2 donate electrons to?

Answer 10

NADH - Complex I
FADH2 - Complex II

Question 11

Where is cytochrome c found?

Answer 11

In between Complexes III and IV

Question 12

Presence of which element in ETC complexes allows NADH and FADH2 to donate their electrons?

Answer 12

Iron (Fe)

Question 13

How is it possible to pass electrons from one complex to another?

Answer 13

It is energetically favourable as electrons progress along the chain, they lose energy

Question 14

How is oxygen allowed to accept electrons from Complex IV?

Answer 14

A more positive E0 implies a higher tendency to accept electrons

Question 15

What are the components of ATP synthase and their locations?

Answer 15

F0 - membrane bound
F1 - Projecting into the matrix

Question 16

What are the subunits of F0 and F1 of ATP synthase?

Answer 16

F0 - a, b, c
F1 - α, β, γ

Question 17

What are the 2 functions of ATP synthase?

Answer 17

Question 18

Why are cyanide (CN) and azide (N3) considered poisons?

Answer 18

They bind with high affinity to the ferric (iron III) form of the haem group in complex IV blocking the flow of electrons through ETC and stopping ATP production

Question 19

Why does malonate’s close resemblance to succinate make it a metabolic poison?

Answer 19

Acts as a competitive inhibitor of succinate dehydrogenase (complex II) - effectively slowing down the flow of electrons from succinate to ubiquinone by inhibiting the oxidation of succinate to fumarate

Question 20

Why is DNP fatal?

Answer 20

It allows protons to pass the membrane bypassing ATP synthase, uncoupling proton flow from ATP synthesis

Question 21

What is non-shivering thermogenesis?

Answer 21

Activation of UCP-1 which bypasses ATP synthase, in newborns, to release energy of proton flow as heat energy due to a drop in core body temp

Question 22

How does Rotenone interfere with the ETC?

Answer 22

Inhibits the transfer of electrons from Complex I to Coenzym Q

Question 23

What is the name of the antibiotic that interferes with ATP production and what’s the mechanism?

Answer 23

Oligomycin - binds to the stalk of ATP synthase blocking the flow of protons through the enzyme