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biochem 2 > Free Radicals and Antioxidants > Flashcards

Free Radicals and Antioxidants Flashcards

1
Q

propertoes of oxygen in ground state

A

can absorb energy from light, porphyrins or other sources and get to the exicted state

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2
Q

how is superoxide anion generated

A

one electron reduction of molecular oxygen, usually invovling a metalb catalyst

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3
Q

how is hydrogen peroxide generated

A

transfer of 2 electrons

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4
Q

how is hydroxyl radical generates

A

transfer of 3 electrons.

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5
Q

which of the oxygen radicals is the most reactive

A

hydroxyl radical

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6
Q

how do you get reactive oxygen from ETC

A

quinone in complex III gets oxidized to form superoxide anion

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7
Q

how do you get reactice oxyen from NADPH/cytochrome oxidases

A

if second transfer of electrons fails, superoxide anion is released from enzyme

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8
Q

chronic alcohol consumption stresses the liver in what 2 ways

A

oxidative stress from hydrogen peroxide

DNA damage

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9
Q

what reactive oxygen does the xanthine oxidase reaction produce

A

hydrogen peroxide

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10
Q

how are iron and copper involved in free radicals

A

free iron and copper irons can donate an electron to molecular oxygen or hydrogen peroxide

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11
Q

what is iron boudn to

A

ferritin and transferrin

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12
Q

what is copper bound to

A

ceruloplasmin

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13
Q

what causes hereditary hemochromatosis

A

mutation in HFE gene

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14
Q

symptoms of hereditary hemochromtosis

A

destruction of liver, pancreaus, and heart muscle cells

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15
Q

where is superoxide dismutase (SOD) exxpressed

A

cytoplasm and mitochondria

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16
Q

SOD function

A

convert superoxided into hydroen perodxide

17
Q

catalase

A

heme containing enzyme that detoxes hydrogen perdoixe

18
Q

glutathione peroxidase

A

uses electrons to reudce hydrogen peroxide

19
Q

ascorbic acid

A

water soluble electron donor to free radicals

20
Q

vitamine E

A

lipi solube radical scapventure

21
Q

waht does vit E protect against

A

damage from free radicals as well as from lipid peroxidation

22
Q

how does vit A reduce oxidative damage to membranes

A

electron donor for reduction of radicals

quenches vibration energy of singlet oxygen

23
Q

GSH

A

has thiol group that can donate elctron to radical, becomes oxidized

24
Q

how is GSSG reduceed back to GSH

A

glutathione reductase

25
Q

polyphenols

A

water soluble antioxidants that are in plant extracts

26
Q

where do most electrons originate from

A

NADPH

27
Q

how does glutathione peroxidase help fight radical damage in RHCs

A

destroy hydrogen and organic peroxides

28
Q

how does SOD help fight radical damage in RBCS

A

destroy superoxide

29
Q

how does catalase right radical damage in RBCs

A

convert hydrogen peroxide

30
Q

what in RBCs directly reacts with ROS

A

RSH, vit C, vit E

31
Q

how does methemoglobin help fight radical damage in RBCs

A

methemoglobin reductase reparis oxidative damage by reducing iron, convert methemoglboin back to hemoglobin

32
Q

when is oxidative stress present

A

when conc of ROS exceeds cell capcity for detox

33
Q

what is oxidative stress daaming to

A

lipids, DNA, proteins

34
Q

the most serious damage by hydroxyl radical to membrans is what

A

peroxidation of polyunsaturated fatty acids

35
Q

process of lipid peroxidation

A

1) hydroxyl radical takes electron from PUFA, produces lipid radical
2) lipid radical react with oxygen to form lipid peroxides
3) liipd peroixes are unstable and take elctrons

36
Q

what is a good marker for oxidative stress

A

plasma malondialedhyde conc

37
Q

how does hydroxyl radical fuck up DNA

A

produces DNA double stranded breaks

38
Q

what forms peroxynitirite

A

superoxide and peroxynitrate anions

biochem 2 (22 decks)

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