Session 10 - Managing Oxidation

Question 1

What are antioxidants?

Answer 1

Molecules that protect other molecules from a chemical process called oxidation.

Question 2

What is oxidation?

Answer 2

A common chemical reaction where electrons are transferred from 1 molecule to another. The antioxidant sacrifices itself and is oxidised instead of the other molecule, becoming the free radical.

Question 3

What do all oils contain?

Answer 3

Vitamin E which protects lipids from becoming oxidated - especially PUFA’s

Question 4

What are these antioxidants?

Answer 4

Vitamins, minerals, enzymes, or plant derived nutrients.

Question 5

What are the two lines of cellular antioxidant defence?

Answer 5

In the membrane: Vit E, beta-carotene, coQ10

Intracellular: Vit C, glutathione per, superoxide dismutase (SOD), & catalase

Question 6

What are endogenous and exogenous antioxidants?

Answer 6

Endogenous are antioxidants produced in our body incl enzymes & molecules such as:

glutathione (GSH) peroxidase, catalse, superoxide dismutase and thioredoxin.

Question 7

What are exogenous antioxidants?

Answer 7

Dietary antioxidants - vit c, tocopherols, flavonoids, carotenoids, lipoic acid, and selenium.

Question 8

True/False - A free radical is an unstable atom/molecule that has at least one unpaired electron in an atomic orbital.

Answer 8

True

Question 9

True/False - free radicals are not produced in the human body during our normal metabolic processes.

Answer 9

False

Question 10

Explain the damage caused by free radicals in a human body. How do free radicals harm human body cells?

Answer 10

Causes DNA and intracellular organelle damage.
Damages protein structures -
Damages lipids: all cell membranes, cholesterol, fat breakdown.

Question 11

List 3 endogenous antioxidants in our body.

Answer 11

• Glutathione peroxidase
• Catalase
• Superoxide dismutase

Question 12

Which of the following enzymes are not used to eliminate hydrogen peroxides in our cells?
Glutathione, Catalase, Superoxide dismutase (SOD, Vitamin C.

Answer 12

Superoxide Dismutase (SOD)

Question 13

What are Reactive Oxygen Species (ROS)?

Answer 13

Highly reactive chemicals formed from oxygen

Question 14

List examples of Reactive Oxygen Species? (ROS)

Answer 14

Peroxyl
Hydrogen peroxide
Hydroxyl

Question 15

What are the importance of enzymes in relation to ROS?

Answer 15

Enzymes scavenge and neutralise ROS into less noxious molecules.

Question 16

What causes generation of ROS in the human body?

Answer 16

Radiation exposure
Arachidonate pathway
Electron Transport chain

Question 17

What antioxidants are produced endogenously in the body?

Answer 17

Catalase

Glutathione

Question 18

T/F - Peroxidase is an enzyme that assists in the elimination of superoxide radicals in the body.

Answer 18

False - superoxide dismutase is an enzyme that assists elimination of superoxide radicals in the body.

Question 19

What are the key nutrients required for function of superoxide dismutase?

Answer 19

Manganese
Copper
Zinc

Question 20

Give examples of enzymes that scavenge specific ROS

Answer 20

Hydrogen peroxide: Glutathione peroxidase
Hydrogen peroxide: Catalase
Hydrogen peroxide: Myeloperoxidase (heme iron dependent enzyme)

Question 21

What are asthmatics often deficient in?

Answer 21

Glutathione

Question 22

True/False - Superoxide dismutase is an endogenous enzyme that generates hydrogen peroxides while removing free radicals

Answer 22

True - SOD manages superoxide ion and while doing so, produces hydrogen peroxide which is further addressed by other endogenous antioxidants and converted to harmless molecules: water & oxygen.

Question 23

True or False - Exposure to gamma rays may generate hydroxyl radical in the body.

Answer 23

True - Gamma rays split water in the body to form the hydroxyl radical

Question 24

True or False - Excess free iron can generate hydroxyl ion in the body.

Answer 24

True - via the fenton reaction. Excess ferrous may react with hydrogen peroxide to produce the hydroxyl radial.

Question 25

Which antioxidants quenches lipid peroxides in the body?

Answer 25

Glutathione
Vitamin E
CoQ10

Question 26

T/F All antioxidants are left useless after removing free radicals.

Answer 26

False - many antioxidants are able to regenerate after removing free radicals meaning they can be reused. Ascorbic acid is an example of an antioxidant that is able to regenerate others.

Question 27

True or False - Dihydrolipoic acid only regenerates CoQ10

Answer 27

False - Dihydrolippoic acid regenerates vitamin C, glutathione and CoQ10

Question 28

What is the nutrient glutathione peroxidase is dependent on?

Answer 28

Selenium

Question 29

What nutrient activates or regenerates glutathione?

Answer 29

Vitamin C