Free Radicals Flashcards

1
Q

deficiency in this impairs the ability of an erythrocyte to form NADPH resulting in hemolysis

A

glucose 6 phosphate dehydrogenase

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2
Q

generates superoxide radicals

A

cytochrome P450

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3
Q

not a free radical since it has no unpaired electrons, but is still a reactive oxygen species

A

hydrogen peroxide

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4
Q

what are the 3 isoenzymes of superoxide dismutase (SOD)

A

1 and 2. extracellular and cytosolic SOD (require zinc an copper cofactors)
3. mitochondrial SOD (require manganese cofactor)

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5
Q

what 4 ways can hydrogen peroxide be made

A
  1. ascorbate by eliminating superoxide radicals
  2. enzyme xanthine oxidase
  3. enzyme amine oxidase
  4. diffuse through water and lipids and move through cells and tissues to cause damage
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6
Q

hydrogen radicals are also produced from a reaction between hydrogen peroxide and superoxide radicals (non-enzymatic)

A

haber-weiss reaction

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7
Q

________ fatty acids are more susceptible to oxidation because they have more double bonds

A

polyunsaturated

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8
Q

singlet molecular oxygen is when an oxygen’s unshared electrons absorbs an energetic photon reaction via

A

photochemical reaction

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9
Q

vitamin A,C,E and minerals such as selenium, zinc, copper, manganese, and iron eleminate

A

free radicals

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10
Q

what aids in elimination of superoxide radicals

A

ascorbate and superoxide radicals

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11
Q

what aids in elimination of hydrogen peroxide

A

ascorbate, glutathione peroxidase, catalase, and myeloperoxidase

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12
Q

to increase glutathione levels, patients must be supplemented with

A

N-acetylcysteine and alpha-lipoic acid

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13
Q

what aids in elimination of hydroxyl radicals

A

ascorbate, glutathione, dihydrolipoic acid, coenyzme Q

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14
Q

vitamin E elimination of lipid carbon and peroxyl radicals: _____ is most effective in its ability to donate hydrogen ataoms

A

alpha-tocopherol

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15
Q

carotenoids elimination of lipid carbon and peroxyl radicals: ___ is most efficient free radical scavenger compared to vitamin E

A

lycopene

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16
Q

_______ most effective of all the carotenoids in quenching singlet oxygen

A

lycopene

17
Q

______ 100x more efficient than vitamin E at quenching singlet molecular oxygen

A

lycopene and beta-carotene

18
Q

___ can act as a pro-oxidant in the absence of co-antioxidants such as vitamin c

A

alpha-tocopherol

19
Q

what is used in vitamin E regeneration

A

ascorbate glutathione or ubiquinone

20
Q

what is used in vitamin C regeneration

A

semidehydroascorbic acid or dehydroascrobate

NADH and dihydrolipoic acid

21
Q

what is used in ubiquinol regeneration

A

ubisemiquinone (DHLA and thioredoxin)

22
Q

what is used in glutathione regeneration

A

oxidized glutathione (DHLA)

23
Q

excess antioxidant depletes ______ and prevents apoptotic death of cancerous cells

A

ROS concentrations