Oxygen Radicals

Question 0

Main source of chronic low level ROS from

Answer 0

Complex I

Question 1

What are the 3 reactive oxygen species?

Answer 1

+ 1 e- superoxide radical
+ 2 e- hydrogen peroxide
+ 3 e- hydroxyl radical + H2O

Question 2

What 2 cellular components produce ROS

Answer 2

Phagocytes

Peroxisomes

Question 3

What is the most damaging form

of ROS and why?

Answer 3

Hydroxyl radical

• high kinetics
• no defense
• can initiate radical chain reactions

Question 4

Radical theory of aging

Answer 4

Lifespan determined by balance between energy for maintenance & repair vs growth & reproduction

Question 5

How does caloric restriction increase lifespan?

Answer 5

Shifts energy usage to favor repair rather than reproduction

Activates mTor

Question 6

What are the 3 most important antioxidant enzyme systems?

Answer 6

Superoxide dismutase (SOD)
Glutathione peroxidase
Catalase

Question 7

Which antioxidant enzyme system is the first line of defense, and why?

Answer 7

SOD because most ROS begin as superoxide

Question 8

What are the 2 isozymes of SOD?

Answer 8

Cu-Zn in cytoplasm and extra cellular space

Mn in mitochondrial matrix

Question 9

Reaction catalyzed by SOD

Answer 9

2 Superoxides + 2H+ –> H2O2 + O2

Question 10

What happens when you have loss of the SOD isoenzymes?

Answer 10

Losing Cu-Zn SOD may lead to ALS

Losing Mn SOD lethal (in mito)