Session 10 - Managing Oxidation Flashcards
What are antioxidants?
Molecules that protect other molecules from a chemical process called oxidation.
What is oxidation?
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.
What do all oils contain?
Vitamin E which protects lipids from becoming oxidated - especially PUFA’s
What are these antioxidants?
Vitamins, minerals, enzymes, or plant derived nutrients.
What are the two lines of cellular antioxidant defence?
In the membrane: Vit E, beta-carotene, coQ10
Intracellular: Vit C, glutathione per, superoxide dismutase (SOD), & catalase
What are endogenous and exogenous antioxidants?
Endogenous are antioxidants produced in our body incl enzymes & molecules such as:
glutathione (GSH) peroxidase, catalse, superoxide dismutase and thioredoxin.
What are exogenous antioxidants?
Dietary antioxidants - vit c, tocopherols, flavonoids, carotenoids, lipoic acid, and selenium.
True/False - A free radical is an unstable atom/molecule that has at least one unpaired electron in an atomic orbital.
True
True/False - free radicals are not produced in the human body during our normal metabolic processes.
False
Explain the damage caused by free radicals in a human body. How do free radicals harm human body cells?
Causes DNA and intracellular organelle damage.
Damages protein structures -
Damages lipids: all cell membranes, cholesterol, fat breakdown.
List 3 endogenous antioxidants in our body.
- Glutathione peroxidase
- Catalase
- Superoxide dismutase
Which of the following enzymes are not used to eliminate hydrogen peroxides in our cells?
Glutathione, Catalase, Superoxide dismutase (SOD, Vitamin C.
Superoxide Dismutase (SOD)
What are Reactive Oxygen Species (ROS)?
Highly reactive chemicals formed from oxygen
List examples of Reactive Oxygen Species? (ROS)
Peroxyl
Hydrogen peroxide
Hydroxyl
What are the importance of enzymes in relation to ROS?
Enzymes scavenge and neutralise ROS into less noxious molecules.
What causes generation of ROS in the human body?
Radiation exposure
Arachidonate pathway
Electron Transport chain
What antioxidants are produced endogenously in the body?
Catalase
Glutathione
T/F - Peroxidase is an enzyme that assists in the elimination of superoxide radicals in the body.
False - superoxide dismutase is an enzyme that assists elimination of superoxide radicals in the body.
What are the key nutrients required for function of superoxide dismutase?
Manganese
Copper
Zinc
Give examples of enzymes that scavenge specific ROS
Hydrogen peroxide: Glutathione peroxidase
Hydrogen peroxide: Catalase
Hydrogen peroxide: Myeloperoxidase (heme iron dependent enzyme)
What are asthmatics often deficient in?
Glutathione
True/False - Superoxide dismutase is an endogenous enzyme that generates hydrogen peroxides while removing free radicals
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.
True or False - Exposure to gamma rays may generate hydroxyl radical in the body.
True - Gamma rays split water in the body to form the hydroxyl radical
True or False - Excess free iron can generate hydroxyl ion in the body.
True - via the fenton reaction. Excess ferrous may react with hydrogen peroxide to produce the hydroxyl radial.
Which antioxidants quenches lipid peroxides in the body?
Glutathione
Vitamin E
CoQ10
T/F All antioxidants are left useless after removing free radicals.
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.
True or False - Dihydrolipoic acid only regenerates CoQ10
False - Dihydrolippoic acid regenerates vitamin C, glutathione and CoQ10
What is the nutrient glutathione peroxidase is dependent on?
Selenium
What nutrient activates or regenerates glutathione?
Vitamin C
