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Micronutrients-Vitamins Flashcards

(72 cards)

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1
Q

name the fat soluble vitamins

A

vitamin A, D, E, and K

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2
Q

name the water soluble vitamins

A

Ascorbic Acid, Energy releasing B vitamins, Hematopoietic B vitamins, other B vitamins

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3
Q

Folic acid (Folate) is vitamin B__. Plays an important role in _____

A

Folate is vitamin B9.

-one-carbon atom transfers

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4
Q

what is the reduced form of folate?

A

tetrahydrofolate

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5
Q

Methotrexate inhibits ___ which prevents the formation of _____. This drug is used to treat psoriasis, rheumatoid arthritis, and neoplastic diseases

A
  • dihydrofolate reductase

- tetrahydrofolic acid (THF)

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6
Q

N10-formyl THF produces

A

purines

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7
Q

N5, N10 -methylene THF produces

A

thymidine monophosphate, serine synthesis from glycine

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8
Q

N5-methyl THF produces

A

methionine synthesis from homocysteine

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9
Q

deficiencies in which vitamins can cause macrocytic anemia?

A

deficiency in vitamin B12 or folate

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10
Q

microcytic anemia can be caused by deficiencies in which vitamins?

A

deficiency in iron, pyridoxine, and ascorbate

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11
Q

which vitamin is important to prevent neural tube defects in the fetus?

A

folate

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12
Q

a patient comes to you complaining of fatigue. The patient has a history of rheumatoid arthritis. Blood tests reveal the patient has macrocytic anemia. What medication could have caused the anemia?

A

methotrexate

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13
Q

What folate related rxn is vitamin B12 (methyl-cobalamin) present in?

A

Homocysteine and N5-methyl-tetrahydrofolate —(methionine synthase)—> methionine and tetrahydrofolate
cofactors: Vitamin B12 (methyl-cobalamin)

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14
Q

a patient presents with elevated homocysteine levels. What do vitamins do you suspect are at fault?

A

vitamin B12(methyl-cobalamin) or Folate (N5-methyltetrahydrofolate)

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15
Q

how many bonds does cobalt make in B12?

A

six

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16
Q

Which form of B12 is commercially bought?

A

cyanocobalamin

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17
Q

Is cobalamin present in plants?

A

NO! This is why strict vegans must take B12 supplements. or eat fortified cereals

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18
Q

R-protein trasnfers B12 through the ___ while Intrinsic factor transports B12 through the ___

A

stomach

intestines

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19
Q

Describe the onset of B12 deficiency

A

B12 is not like other water soluble vitamins because it is stored in the body. It may take several years for clinical symptoms of B12 deficiency to show

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20
Q

The active form of vitamin C is ___

A

ascorbic acid

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21
Q

Main function of ascorbate is as a ___ agent. Vitamin C is required for maintenance of ___ and ____

A

reducing

-normal connective tissue and wound healing

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22
Q

deficiency of vitamin C results in ___ which is best explained by ___

A

scurvy

-deficiency in the hydroxylation of collage which results in defective connective tissue

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23
Q

Vitamin B6 derivatives include

A

-pyridine pyridoxine, pryidoxal, and pyridoxamine

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24
Q

pyridine pyridoxine, pryidoxal, and pyridoxamine are all precursors to the biologically active coenzyme ____

A

pyridoxal phosphate (PLP)

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25
PLP, a derivative of vitamin ___, is a coenzyme for what reactions
B6, | reactions involving amino acids!! **transamination
26
Which vitamin is the only water soluble vitamin with significant toxicity??
pyridoxine
27
Thiamine is vitamin B__
1
28
Thiamine Pyrophosphate is the biologically active form of vitamin __
B1
29
what two famous reactions require TPP?
pyruvate dehydrogenase and a-ketoglutarate dehydrogenase
30
Beriberi is caused by what?
severe thiamine deficiency especially where polished rice is a staple of the diet
31
Wernicke-Korsakoff syndrome
-a thiamine deficiency associated with chronic alcoholism
32
Niacin is vitamin B__
niacin is vitamin B3
33
What is the biologically active coenzyme forms of niacin?
-nicotinamide adenine dinucleotide (NAD+) and NADP+
34
a deficiency of pellagra is caused by
niacin deficiency
35
symptoms of pellagra pass through the 3 Ds, what are they?
dermatitis, diarrhea, dementia
36
a patient comes to you and presents with scaly sores, mucosal changes, and mental symptoms. The live on a farm and eat corn every meal, you suspect____
pellagra due to niacin deficiency
37
Niacin can decrease ___
circulating FFA levels by inhibiting lipolysis. reduction of FFAs leads to decreased in liver triglyceride synthesis
38
Riboflavin is vitamin B___
riboflavin is vitamin B2
39
what are the two biologically active forms of riboflavin?
FMN and FAD: these both reversibly accept two hydrogen atoms
40
Biotin is vitamin B___
vitamin B 7
41
deficiencies of biotin are extremely rare because biotin is widely distributed in food and intestinal bacteria make it. What product could potentially cause biotin deficiency?
raw eggs because avidin tightly binds biotin but for a problem it would require around 20 raw eggs a day
42
Pantothenic acid is vitamin B__
B5
43
pantothenic acid is a component of ___
coenzyme A
44
dietary retinol is better known as Vitamin __
Vitamin A
45
T or F: retinoic acid can be reduced to derive retinal or retinol
False. There is no mechanism in humans for the reduction of retinoic acid and therefore retinoic acid cannot be used to derive either retinal or retinol
46
B-carotene can be cleaved i the intestine to yield two molecules of retinal. Is this conversion effecient?
NO, vitamin A activity of B-carotene is a fraction of retinol
47
what other compound that we know of does Vitmain A act like?
Steroid hormones.
48
describe how retinol travels in blood
retinol travels in plasma by retinol-binding protein
49
how does retinol act in target tissues
retinol is oxidized to retinoic acid which binds to nuclear receptors
50
why does vitamin A deficiency result in night blindness?
11 cis retinal is a component of rhodopsin (the visual pigment)
51
retinol is oxidized to ____. ____ binds with high affinity to specific receptor proteins present in the nucleus of target tissues like epithelial
retinoic acid, retinoic acid
52
T or F: retinoic acid has a vital role in reproduction and the visual cycle
F: Animals given retinoic acid only as their source of vitamin A from birth are blind and sterile
53
acne and psoriasis can be treated with
retinoic acids or derivatives
54
xeropthalmia
- a pathological dryness of the conjunctiva and cornea - due to vitamin A deficiency - most commonly seen in children in developing tropical countries
55
Isotretinoin
-isomer of retinoic acid a teratogen contraindicated in women of childbearing potential unless severe, disfiguring acne and adequate birth control must be used while on it
56
The active molecule of Vitamin D is
1,25-diOH-D3) calcitrol
57
the most prominent actions of 1,25-diOH-D3 are
regulate plasma levels of calcium and phosphorus
58
7-dehydrocholesterol is converted to ___ in the dermis and epidermis of humans exposed to sunlight and transported to the liver bound to vitamin-D binding protein
cholecalciferol (D3)
59
are vitamins D2 or D3 biologically active?
NO
60
calcidiol
- the 25-hydroxycholecalciferol form | - predominant form of vitamin D in plasma and the major storage form of the vitamin
61
1,25-diOH-D3 stimulates the ___ of ___ from _____
- mobilization of calcium from bone | - result is increase in plasma calcium and phosphate
62
1,25-diOH-D3 stimulates the intestinal absorption of
Ca
63
How does 1,25-diOH-D3 stimulates the intestinal absorption of calcium?
-calcium uptake is enhanced by increased synthesis of specific calcium-binding protein, calbindin
64
vitamin D deficiency results in
-net demineralization of bone resulting in rickets
65
renal osteodystrophy
chronic kidney disease decreases formation of active vitamin D as well as increased retention of phosphorus
66
low blood calcium triggers
-increase PTH which causes bone demineralization with release of calcium and phosphate
67
vitamin K is required in the hepatic synthesis of blood clotting proteins ____, and ___, ___, ___
prothrombin, factors VII, IX, and X
68
formation of functional clotting factors requires the vitamin K dependent carboxylation of several _____ to ___ residues
-glutamate residues to γ-carboxyglutamate | (Gla) residues
69
in generating mature clotting factors, vitamin K starts in what form and gets oxidized to what form
-hydroquinone form (Kh) | to epoxide form KE
70
warfarin
inhibits vitamin K epoxide reductase (VKOR) so vitamin K cant get back to hydroquinone form
71
a true vitamin K deficiency is rare because it is produced by
-intestinal flora or obtained in diet
72
why is it recommended that newborns receive a single IM dose of vitamin K?
-newborns have sterile guts and human milk only provides 20% of RDA for vitamin K

CMBL (22 decks)

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