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Foundations 1 > Week 3 (2) Micronutrient Lectrues > Flashcards

Week 3 (2) Micronutrient Lectrues Flashcards

1
Q

what are micronutrients?

A

nutrients that are only required in SMALL (micro) amounts

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2
Q

can we take make micronutrients in sufficient quantitiies?

A

no, we cannot make them in sufficient quantities

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3
Q

what is the major difference between micronutrients and macronutrients?

A

micronutrients are not metabolized directly to provide energy

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4
Q

what are the two large classes of micronutrients?

A

fat soluble (ADEK) and water soluble (C and B complex)

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5
Q

what is another word for micronutrients? 2

A

vitamins and minerals

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6
Q

what is unique about vitamin A? what is the purpose?

A

highly conjugated, able to absorb visible light

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7
Q

like any lipid soluble molecule, the lipid soluble vitamins (ADEK) have to be transported how in blood?

A

via lipoproteins/carrier proteins (chylomicrons, VDL, HDL), but they can easily diffuse across plasma membranes

chylomicrons–>liver–>VLDL(LDL)–>Tissue

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8
Q

where do lipid soluble vitamins accumulate?

A

in body tissues/organs/fat

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9
Q

what is the danger of lipid soluble vitamin accumulation?

A

mega-doses (100x RDA), can lead to metabolic consequences

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10
Q

Vitamin D deficiency is linked to which bone disorder?

A

rickets

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11
Q

Vitamin D is derived from what?

A

sterols

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12
Q

what is a pro-vitamin?

A

a vitamin that is not yet in its active form

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13
Q

how is the vitamin D3 pro-vitamin activated?

A

UV light

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14
Q

Vitamin D3 is the precursor for what active endgoenous metabolite?

A

calcitriol

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15
Q

in order for vitamin D3 to be converted/activated to calcitriol what must occur

A
  1. pro-vitamin is activated by UV light to form vitamin D3

2. D3 must be hydroxylated twice (in liver and then in kidney) to form the active calcitriol

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16
Q

the formation of calcitriol is regulated at what level?

A

in the kidney/bone during the second hydroxylation event

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17
Q

what is the function of calcitriol?

A

maintains plasma calcium homeostasis in conjunction with PTH (promotes transcription of genes associated with calcium uptake from duodenum)

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18
Q

a decrease in plasma Ca will cause what?

A

an increase in parathyroid hormone–>an increase in calcitriol–>increase in Ca absorption in intestines

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19
Q

vitamin D deficiency can lead to what in adults?

A

osteoporosis. a decrease in bone mass and fragile bones

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20
Q

what are some conditions associated with vitamin D toxicicty (>10X RDA)

A

hypercalcemia, calcium deposits in kidney and heart

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21
Q

when we say that vitamins are a family of molecules what does that mean?

A

A mixture of forms all of which have some activity. Ex. Vitamin A comprises a family of molecules containing a 20 carbon structure….retinal and retinoic acid

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22
Q

what is the biologic function of vitamin A? 2

A

vision: retinol binds rhodopsin and when light hits it, it is converted to the all trans form

gene expression: retinoic acid binds receptor and regulates expression of genes associated with proliferation and differentiation (integrity of epithelial cells, maintain immune function, embryonic development)

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23
Q

what is the active from of Vitamin A? (2)

A

retinol (eyes), retinoic acid (gene expression)

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24
Q

Vit A deficiency causes? 2

A

night blindness, skin lesions

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25
Q

vitamin E has how many naturally occurring forms?

A

8, all hydrophobic in nature

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26
Q

what is fxn of Vit E?

A

anti-oxidant (non-specific) protect poly-unsaturated FAs from becoming oxidized. a specific metabolic fxn has yet to be found

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27
Q

where do you find Vit E most commonly?

A

found in commercially produced oils and lotions to preserve them

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28
Q

Vitamin K is acquired how?

A

diet and intestinal bacteria

29
Q

what is the role of Vit K? 2

A

cofactor in carboxylation reactions (plays role in calcium binding). carboxylated products important in coagulation and stimulation of bone and mineral maturation

30
Q

if you are def in VIt K?

A

bleeding, lack of clotting

31
Q

is vit K def common?

A

rare in adults but more common in infants due to sterile guts

32
Q

what is vitamin E def?

A

none discovered

33
Q

compared to the fat soluble vitamins, the water soluble vitamins are much more

A

polar (O, N, charged)

34
Q

which water soluble vitamin is conjugated?

A

Vitamin B (light sensitive, store in dark to prevent degradation)

35
Q

how are water soluble micronutrients absorbed

A

CANT diffuse across membranes, need membrane transporters

36
Q

are water soluble micronutrients easy to overdose on?

A

no, they are more easily excreted than the lipid soluble ones AND they saturate membrane transport proteins (M-M kinetics)

37
Q

in general, the water soluble vitamins and minerals play an important role in…

A

once processed, serve as co-factors for different metabolic (energy producing) pathways. NAD, FAD, CoA

38
Q

Thiamin is also called

A

B1

39
Q

what is the active form of B1

A

TPP

40
Q

what is the fxn of thiamin?

A

important co-factor for metabolic enzymes. Ex: pyruvate dehydrogenase complex

41
Q

what is the fxn of thiamin?

A

important co-factor for metabolic enzymes. Ex: pyruvate dehydrogenase complex…others

42
Q

what is the source of thiamin? 3

A

whole grains, enriched flour, meats

43
Q

factors that destroy thiamin? 3

A

heat, thiaminase (raw fish), tannins

44
Q

thiamin deficiency**

A

Beriberi (be able to associate beriberi and thiamin deficiency)

45
Q

vitamin B2 is also called

A

riboflavin

46
Q

what is riboflavin converted to?

A

FAD (succinate dehydrogense requires this)

47
Q

where can we get riboflavin? 5

A

milk, grains, meat, poultry, fish

48
Q

another name for B3 is

A

niacin

49
Q

niacin is converted to?

A

NAD and NADP

50
Q

Niacin can be made from…

A

Tryptophan

51
Q

niacin deficiency disease***

A

the 3 D’s Dermatitis, Dementia, Diarrhea

52
Q

B5 is aprecursor for

A

CoA (TCA cycle!, beta oxidation)

53
Q

B6 is a family of

A

a group of 6 pyrimidine derivatives

54
Q

are vitamin B deficencies commonq

A

no, they are in abundance in our diets

55
Q

are vitamin B deficencies commonq

A

no, they are in abundance in our diets

56
Q

B6 fxn?

A

a coenzyme for >100 enzymes. w/o B6 all AA become essential

57
Q

Vitamin B7 AKA

A

biotin

58
Q

role of biotin

A

coenzyme in carboxylation reactions (pyruvate carboxylase)

59
Q

B9 aka

A

Folic acid

60
Q

folic acid role

A

carbon metabolism (AA, purine and thymidine synthesis)

61
Q

B12 family role

A

involved in methionine synthesis (coenzyme for methionine synthetase)

62
Q

what is unique about B12 absorption?

A

unlike other water soluble vitamins, it requires a protien (intrinsic factor) to be absorbed in the intestines

63
Q

Vitamin C aka

A

ascorbic acid

64
Q

role of Vit C (2)

A

anti-oxidant, aids hydroxylation (important in collagen formation)

65
Q

Vit C deficiency

A

Scurvy: failure to cross-link collagen (weak bones)

66
Q

important Minerals

A

Fe (Hb), I (thyroid), Zn, Se

67
Q

Keshan disease associated with what mineral def?

A

Se

68
Q

Selenium role?

A

forms selenoproteins that play a role in defending against oxidative damage, disulfide bond homeostasis, thyroid hormone metabolism

69
Q

Zn fxn

A

essential in fxn of many enzymes and TFs

Foundations 1 (65 decks)

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