Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Biochem III > Free Radicals and Antioxidants > Flashcards

Free Radicals and Antioxidants Flashcards

1
Q

What is the most reactive ROS?

A

hydroxyl radical

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What cytochrome p450 isoform is responsible for alcohol degradation?

A

CYP450E1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What type of radical does CYP450E1 produce?

A

hydroxyethyl radical

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are the five sources of ROS?

A

quinone

NADPH/cytochrome oxidase

CYP450E1

xanthine oxidase

Free iron and copper ions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How do free iron and copper contribute to the production of ROS?

A

by donating an electron to molecular oxygen or hydrogen peroxide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is Iron bound to?

A

ferritin or transferrin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is copper bound to?

A

ceruloplasmin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What protein in heme provides protection against oxidation?

A

globin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How can radiation kill cancer?

A

radition can split a water molecule into hydrogen and hydroxyl radical

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the function of superoxide dimutase?

A

to convert superoxide radical into H2O2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the function of catalase?

A

to convert hydrogen peroxide into water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the function of ascorbic acid?

A

water soluble electron donor to many types of free radicals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Where is vitamin E present? What is its function?

A

membranes. radical scavenger.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Vitamin E prevent what two types of damage?

A

damage from free radicals and lipid peroxidation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What property gives vitamin A its ability to reduce oxidative damage to membranes?

A

series of unconjugated double bonds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How does glutathione protect against oxidative stress?

A

glutathione can donate an electron to a free radical from its thiol group and form a homodimer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is another name for polyphenols?

A

Flavonoids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are polyphenols?

A

water soluble antioxidants found in green tea, grapes, red wine and chocolate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is a major antioxidant of the cytoplasm?

A

uric acid

20
Q

What water insoluble compound can donate an electron to free radicals?

A

bilirubin

21
Q

After donating an electron, what does bilirubin become?

A

biliverdin

22
Q

How do antioxidants become reduced after they donate an electron?

A

mostly by NADPH

23
Q

What in RBCs tends to promote oxidative damage?

A

high oxygen content

24
Q

What compound in RBCs destroys hydrogen and organic peroxides?

A

glutathione peroxidase

25
Q

What three components of RBCs directly react with ROS?

A

GSH, Vitamin C and Vitamin E

26
Q

What is the function of methemoglobin reductase?

A

to replace oxidized iron in heme

27
Q

What molecule can extract an electron from the iron in heme?

A

hydrogen peroxide

28
Q

What is the most serious damage to membrane by radicals?

A

peroxidation of polyunsaturated fatty acids

29
Q

What are the three steps to lipid peroxidation?

A
  1. hydroxyl radical removes electron from PUFA
  2. lipids fadicals form lipid peroxides
  3. Lipid peroxides abstract electrons from other PUFAs
30
Q

What lipid peroxidation product is mutagenic?

A

Malondialdehyde

31
Q

Why is malondialdehyde mutagenic?

A

malondialdehyde reacts with purine bases in DNA

32
Q

Plasma concentration of what is a good marker for oxidative stress?

A

malondialdehyde

33
Q

Hydroxyl radical does the most serious damage to what?

A

DNA

34
Q

What does hydroxyl radical do to DNA?

A

produces double-stranded breaks

35
Q

In proteins, what do ROS extract electrons from?

A

thiol groups

36
Q

What does removing electrons from thiol groups do?

A

produces incorrect double bonds

37
Q

Is nitric oxide a free radical?

A

Yes

38
Q

What is peroxynitrite formed from?

A

superoxide and peroxynitrate

39
Q

What vitamin has an extensive system of conjugated double bonds?

A

Vitamin A

40
Q

Excluding glutathione, what are three other metabolic antioxidants?

A

uric acid, bilirubin, polyphenols

41
Q

What reduction equivalent is capable of reducing antioxidant?

A

NADPH

42
Q

What makes malondialdehyde mutagenic?

A

It reacts with purine bases

43
Q

Can malondialdehyde be measured?

A

yes. it is a good measure of oxidative stress.

44
Q

What base can hydroxyl radical bond with?

A

guanine

45
Q

In proteins, ROS extract an electron from what group?

A

thiol

46
Q

What is peroxynitrite formed from?

A

peroxynitrate and superoxide

Biochem III (9 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions