Antioxidants Flashcards

1
Q

what are examples of stressors?

A

aging, wounding, xenobiotics, radiation/light, heat and cold, heavy metals, pollutants, hormones

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2
Q

notable RNS?

A

nitric oxide, nitrogen dioxide

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3
Q

places where free radicals are made?

A

mitochondria; vacuoles; nucleus, lysosomes, peroxisomes, ER, cyto, membrane

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4
Q

what is singlet oxygen involved in?

A

skin, photodamage

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5
Q

what cause production of free radicals?

A

smoking, strenuous exercise

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6
Q

how is superoxide radical created?

A

O2 react with catecholamines, semiquinone intermediate in mito, NADPH oxidase in membrane, drug/toxin metabolism (WBCs)

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7
Q

H2O2 is produced by ____

A

SODs (superoxide dismutases); rxn ascorbate with O2

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8
Q

H2O2 is produced in:

A

peroxisomes, activated neutrophils, ischemia-reperfusion

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9
Q

this radical is a “severe threat to living systems”, form when exposed to gamma rays and in Haber-Weiss and Fenton rxns

A

hydroxyl radical

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10
Q

a peripheral e- excited to a higher state, and mroe rxtive than ground state Oxygen

A

singlet molecular oxygen

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11
Q

how is singlet oxygen formed?

A

via photochemical rxn, enzymatic rxns (resp bursts), peroxidations

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12
Q

in lipid peroxidation, O2 is slow oxidant in ___ phase, fast oxidant in ___ phase

A

initiation; propagation

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13
Q

proteins most reactive?

A

proline, histidine, argenine, cysteine

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14
Q

lipid peroxidation releases rxtive ___

A

aldehydes

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15
Q

diseases involving oxidative stress

A

inflammation (arthritis, alzheimer’s, MS, infection), cancer, atherosclerosis, ischemia-reperfusion, aging

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16
Q

ischemia is caused by:

A

cessation of blood/oxygen supply

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17
Q

3 ways to defend against prooxidants:

A

prevent formation, intercept, repair damage

18
Q

interception can be by ___ antioxidants and ____ enzymes

A

classical; phase 2

19
Q

phase 2 enzymes catalytically remove proox and ___ for excretion

A

conjugate

20
Q

classical antiox prevent urther damaging activity, called “____” antioxidant

A

chain-breaking

21
Q

examples of small watersoluble antiox

A

glutathione, uric acid, vit. c

22
Q

ex. of small lipid soluble antiox

A

vit. E, betacarotene, coenzyme Q

23
Q

protein antiox intracellular examples

A

SOD 1+2,glutathione peroxidase, catalase, ferritin

24
Q

protein antiox cell mem examples

A

phopholipid hydroperoxide

25
Q

protein antiox extracell ex

A

SOD 3, ecGPx, plasma proteins (albumin)

26
Q

essential diet antiox

A

vit E and C, minerals, sulfur amino acids (glutathione)

27
Q

nonessential diet antiox

A

carotenoids, lipoic acid, uric acid, coenzyme Q, flavonoids, polyphenols, phytochemicals

28
Q

GPx (glutathione peroxidase) contains __ Se

A

4

29
Q

AH2 + H2O2 –> ?

A

DHA + 2 H2O

30
Q

2 GSH + H2O2 –> ?

A

GSSG + 2 H2O

31
Q

catalase largely present in ____

A

peroxisomes, WBC/RBC

32
Q

catalase turns 2 H2O2 into ___ + ___

A

2 H2O; O2

33
Q

scavengers of OH radical?

A

vit C, uric acid, DHLA, GSH, SH proteins

34
Q

AH2 + OH* –> ?

A

H2O + AH*

35
Q

AH2 + 1O2 –> ?

A

AH* + O2* + H

36
Q

carotenoid + 1O2 –> ?

A

carotenoid* +O2

37
Q

carotenoid* –> ?

A

carotenoid + heat

38
Q

1O2 is ___ by carotenoids

A

quenched

39
Q

vit E regen by:

A

ubiQH2, vit C

40
Q

ubiQH2 regen by:

A

mito reductases (NADH or succinate)

41
Q

vit C regen by:

A

dismutation, GSH, DHLA

42
Q

the reaction: 2 AH* –>AH2 + DHA is referred to as ____

A

dismutation