Lecture 24

Question 1

Where does oxidative phosphorylation occur?

Answer 1

The inner mitochondrial membrane

Question 2

What catalyses the ETC?

Answer 2

Four separate complexes. Complex 1, 2 ,3 ,4 and ATP synthase is sometimes called Complex 5

Question 3

What are the electrons carriers in the ETC?

Answer 3

Coenzyme Q, FMN, Cytochromes and Iron-Sulfur groups

Question 4

What are some uncoupling agents and inhibitors of the ETC

Answer 4

1. Inhibitors - Oligomycin inhibits ATP synthase
2. Uncouplers - Such as dinitrophenol disrupt proton gradient
3. Pesticides such as rotenone prevent transfer of electrons from complex 1 to coenzyme Q
4. Poisons e.g. cyanide prevent the reduction of oxygen

Question 5

What is required to reduce O2 to H2O?

Answer 5

4e- and 4H+

Question 6

What happens when there is the transfer of a single e- to O2?

Answer 6

The superoxide anion is produced O2-

Question 7

What is bad about the free radical?

Answer 7

It tends to steal an electron from another species thus creating a chain reaction

Question 8

What is oxidative stress ?

Answer 8

The level of oxidative damage in a cell, tissue or organ caused by ROS

Question 9

How is damage from ROSs limited?

Answer 9

Antioxidant enzymes and antioxidant vitamins, these neutralise ROS