Brainscape's Knowledge GenomeTM

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


See full index

CMBM 3 > Nutrition and Antioxidants > Flashcards

Nutrition and Antioxidants Flashcards

1
Q

Is vitamin E (lipid/water) soluble?

A

lipid

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

Is Vitamin C (lipid/water) soluble?

A

water

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

Define Reactive Oxygen Species (ROS)

A

superoxide and its subsequent products

-O2 will often steal an electron from reduced metals, flavins, quinols, etc become “superoxide” or O2-

  • very reactive
  • will combine with anything
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Give example of a Reactive Nitrogen Species.

A

gas hormone nitric oxide (NO)

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

Give some examples of Reactive Oxygen Species.

A 
Superoxide (O2-)
Hydrogen Peroxide (H2O2)
Hydroxyl radical (OH-)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Oxidative and Nitrosative damage are commonly linked with disease either as a cause or side-effect.

A

FYI

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

What are four ways that oxidative and nitrosative stress can damage biological molecules?

A
  1. Modification of structure and function of CARBOHYDRATES
  2. Modification of structure and function of PROTEINS
  3. Modification of LIPID (peroxidation)
  4. Modification of individual NUCLEOTIDE BASES
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How do ROS damage lipids?

A

ROS can led to chain reaction due to oxygen reacting with lipid.

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

Why are aldehydes so reactive?

A

create crosslinks between proteins

ex) formaldehyde

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

Patient is suffering from ischemia/reperfusion injury. Damage is primarily caused by:

A

initial return of oxygen to normal levels

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

LDLs are protected from oxidative modification in systemic circulation due to presence of circulating anti-oxidants. What happens when LDLs are trapped in the sub-endothelial space?

A

ROS reacts with LDL and leads to oxidized LDL (oxLDL).

oxLDL

  • is a chemoattractant to circulating monocytes
  • contributes to endothelial dysfunction
  • further ROS formation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How does cytochrome C function in mitochondrial injury?

A

acts as an apoptic signal

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

Iron can play the following roles:

A

role in many enzymes

  • catalysis
  • electron transfer
  • oxygen transport
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What reaction can iron catalyze?

A

Haber-Weiss-Fenton reactions

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

Describe the reactions that iron can undergo.

A

oxidation
reduction

Leo (lose electron Oxidized)
Ger (gain electron Reduced)

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

How is iron stored in the body?

A

ferritin
hemosiderin
(mostly in liver)

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

How much iron is required per day to maintain stores with a mixed diet?

A

8 mg per day

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

How is iron taken up by the body?

A

transferrin - specific cell membrane receptors on target cells

Tf-receptor complex is internalized by receptor-mediated endocytosis

Fe is released by acidification

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

How is non-heme taken up by the body?

A

Stimulated:
Vit C
organic acids
Heme

Inhibited:
black tea
cocoa
chamomile

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What happens in the presence of iron excess?

A

hemochromatosis (hereditary defect)

hemosiderosis (dietary overload)

  • alcohol in excess
  • children ingesting Fe supplements

Oxidative stress

Decrese absorption of thyrozine, tetracycline, ciprofaloxacin

possible heart disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What can lead to iron deficiency?

A

diet deficiencies
infection (H. pylori)
inflammation
other vitamin deficiencies (Vit C)

Result: anemias
- can exacerbated other problems (lead poisoning)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What are some defense mechanisms that protect against oxidative stress?

A 
Chemical:
Vitamin C
Vitamin E
B-carotene
Glutathione
Bilirubin

Enzymatic:
Super Oxide Dismutase (SOD)
catalase
peroxidases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Why does the cell have different redox active organic components?

A

Can donate or accept electrons at different electrical potentials

Overlap allows a wide range of reactions

24
Q

Which enzymes protect you from ROS?

A

superoxide dismutase
catalase
peroxidases

25
Q

Which chemicals protect you from ROS?

A

bilirubin
glutathione
Vitamin C
Vitamin E

26
Q

Describe glutathione.

A

Small, modified tripeptide reversible oxidized/reduced
-thiol group

  • good source of eletroncs to reduce ROS
  • regenerated w/electron from NADPH by Glutathione reductase
27
Q

What is the concentration of glutathione?

A

[millimolar]

28
Q

What is the MAIN function of Vitamin E?

A

antioxidant - stops propagation of free-radical damage in membranes

29
Q

Vitamin E will be deficient when there is ?

A

fat malabsorption

30
Q

Bile acids are essential for which vitamin to be absorbed?

A

Vitamin E

31
Q

Where is the bulk of Vitamin E stored?

A

adipose tissue

32
Q

A deficiency in Vitamin E lease to?

A

retinitis pigmentosa

neurological symptoms

33
Q

What is the RDA of Vitamin E?

A

15 mg/day

** does not accumulate in the liver to toxic levels

34
Q

Scavenges oxygen and free radicals

A

Reducing reagent

35
Q

A-tocopherol deficiency can lead to ?

A

ataxia

36
Q

Bioavailability of Vitamin E depends on what 2 things?

A

bile acids
fat content of food
ex) 2x as available when taken with milk vs. orange guide

37
Q

How is Vitamin E oxidized?

A

by w-oxidation by cytochrome P450

38
Q

What is used to regenerate reduced Vitamin E?

A

Vitamin C

39
Q

List three functions of Vitamin C

A

antioxidant
collagen biosynthesis
-proline
-lysine

Synthesis of:

  • adrenal hormones
  • drug metabolism
  • folate metabolism
  • stimulation iron uptake
40
Q

How many electrons can Vitamin C donate?

A

2

41
Q

How can Vitamin C be regenerated?

A

number of different enzymes using electrons from NAD(P)H or by glutathione

42
Q

What is the first thing that is oxidized in plasma under oxidative stress?

A

Vitamin C

43
Q

How does Vitamin C accumulate?

A

intracellularly via specific transporters AND by at least 4 glucose transporters (GLUT 1-4)

44
Q

What is a result of Vitamin C deficiency?

A

Scurvy

45
Q

How does Scurvy present?

A

connective tissue in muscle, skin, blood vessels

hemorrhagia
bleeding gums
weakness
poor wound healing or bone healing

46
Q

What is the RDA for Vitamin C?

A

60 mg/day

47
Q

What can excess (megadoses) of Vitamin C cause?

A

hypoglycemia
kidney stones
indigestion
dissolve teeth enamel (chewable forms)

48
Q

$21 to 25 billion dollars is spent on supplements each year yet most are not supported by?

A

larger, randomized trials

49
Q

Present evidence on the use of multivitamins (MVMs) is ?

A

insufficient

50
Q

In the primary prevention of total cancer incidence or cancer mortality, Vitamin C, E or beta carotene offer?

A

no overall benefit

51
Q

Regarding cardiovascular events among women with high risk for CVD, ascorbic acid, Vitamin E or beta carotene offer?

A

no overall effect

52
Q

Evaluating the risk of prostate or total cancer, the use of Vitamin E or C offers?

A

no overall effect

53
Q

The risk of major cardiovascular events in men, the use of Vitamin E or C offer?

A

no overall effect

54
Q

Higher plasma Vitamin C levels and fruit and vegetable intake were associated with

A

decreased risk of diabetes

55
Q

The groups most vulnerable to inadequacy of one or more nutrients are?

A
  • older adults
  • pregnant women
  • people who are food insecure
  • alcohol-dependent individuals
  • strict vegetarians and vegans
  • increased needs due to health conditions
  • chronic use of medication that decreases nutrient absorption or changes metabolism
56
Q

What benefit could pharmacologic doses of ascorbate provide?

A

prooxidant and decrease growth of aggressive tumor xenografts (in mice)

57
Q

What was the effective concentration (sufficient to kill 50% of tumor cells) of ascorbate?

A

<10mM for 75% of tumor cells tested

CMBM 3 (28 decks)

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