Chapter 9: Vitamins (overview + Vitamin C) Flashcards

1
Q

organic, essential nutrients in minute amounts

aka “accessory growth factors”

do not yield energy when broken down but assist enzymes with energy production

A

vitamins

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2
Q

organic compounds present in small amounts and are essential for normal health and growth

A

vitamins

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3
Q

vitamins: gen charac and functions

not catabolized as a source of energy and are not used for structural purposes

many vitamins serve as _____

A

coenzymes

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4
Q

vitamins: gen charac and functions

most vitamins cannot be used in the form in which they are absorbed

some must be converted into its _____

ex: vitamin a

A

active form

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5
Q

vitamins: classification acc to solubility

includes vitamins a, d, e, k

A

fat-soluble vitamins

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6
Q

classification acc to solubility

include vitamin c and b-complex vitamins:
thiamin b1
riboflavin b2
niacin b3
pantothenic acid b5
pyridoxine b6
biotin b7
folate b9
cobalamin b12

A

water-soluble vitamins

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7
Q

related substances

2 group of compounds that are chemically related to vitamins and with of nutritional importance

A

provitamins
antivitamins

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8
Q

related substances

chemical precursors of vitamins that are converted with the body to active vitamins

ex: beta-carotene converted to vitamin a in the intestinal wall

A

provitamins

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9
Q

related substances

or antagonists are substances chemically related to true vitamins but cannot perform he biologic function of the true vitamins

ex: avidin present in raw and dried egg white that prevents the utilization of biotin

A

antivitamins

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10
Q

water-soluble vitamins

other names of vitamin c (4)

A

ascorbic acid
antiscorbutic factor
cevitamic acid
hexuronic acid

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11
Q

vitamin c: chemistry

a compound with _____ carbons closely related to the monosaccharide glucose

A

6 carbons

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12
Q

vitamin c: chemistry

vitamin is stable to _____ but easily destroyed by oxidation, light, alkali, and heat, esp. in the presence of iron and copper

these properties make it the most unstable vitamin

A

acid

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13
Q

vitamin c: chemistry

vitamin is stable to acid but easily destroyed by _____ (5), esp. in the presence of iron and copper

these properties make it the most unstable vitamin

A

oxidation, light, alkali, and heat

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14
Q

vitamin c: chemistry

vitamin is stable to acid but easily destroyed by oxidation, light, alkali, and heat, esp. in the presence of _____ and _____

these properties make it the most unstable vitamin

A

iron and copper

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15
Q

vitamin c: chemistry

exist in 2 forms

the oxidized form, dehydroascorbic acid, also has vitamin c activity

A

reduced and oxidized

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16
Q

vitamin c: chemistry

high levels of vitamin c are found in? (5)

A

pituitary and adrenal glands, eyes, white blood cells, and brain

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17
Q

vitamin c: absorption, transport, and utilization

absorbed in the _____ by sodium-dependent active transport system; a simple diffusion at a lower rate

A

jejunum

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18
Q

vitamin c: absorption, transport, and utilization

absorbed in the jejunum by _____; a simple diffusion at a lower rate

A

sodium-dependent active transport system

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19
Q

vitamin c: absorption, transport, and utilization

the degree of absorption decreases as the intake increases.

On average, about 90% of the nutrient is absorbed when the daily intake ranges between _____

A

20-120 mg

20
Q

vitamin c: absorption, transport, and utilization

unabsorbed vitamin c in the large intestine creates an _____ like sugars resulting in watery stools or diarrhea

A

osmotic effect

21
Q

vitamin c: absorption, transport, and utilization

unabsorbed vitamin c in the large intestine creates an osmotic effect like sugars resulting in _____ or _____

A

watery stools or diarrhea

22
Q

vitamin c: absorption, transport, and utilization

transported in the _____, moving freely into body cells

A

blood

23
Q

vitamin c: absorption, transport, and utilization

concentration is found in the ____ and the _____; tissue concentration exceeds the plasma level by 3-10 times

A

adrenal gland; retina

24
Q

vitamin c: absorption, transport, and utilization

consumption of _____ per day can increase the total body pool to a level of 1.2-2.0 g that is sufficient to protect the body from scurvy for 90 days

A

100 mg

25
Q

vitamin c: absorption, transport, and utilization

consumption of 100 mg per day can increase the total body pool to a level of _____ that is sufficient to protect the body from scurvy for 90 days

A

1.2-2.0 g

26
Q

vitamin c: absorption, transport, and utilization

consumption of 100 mg per day can increase the total body pool to a level of 1.2-2.0 g that is sufficient to protect the body from scurvy for _____

A

90 days

27
Q

vitamin c: absorption, transport, and utilization

vitamin c deficient diet declines the pool at a rate of about 3% a day until it reaches _____; signs of scurvy start to appeat

A

300 mg

28
Q

vitamin c: absorption, transport, and utilization

the body maintains a plasma vitamin c level of

A

1.2-1.5 mg/100 ml

29
Q

vitamin c: absorption, transport, and utilization

degradation products

A

diketo-l gulonic acid

30
Q

vitamin c: absorption, transport, and utilization

excess and unmetabolized vitamin is excreted in the

A

urine

31
Q

relationships with other nutrients

prevents the oxidation of (4)

A

vitamins a, c, folic acid, and polyunsaturated fatty acids

32
Q

relationships with other nutrients

prevents the oxidation of THF

A

tetrahydrofolate

33
Q

relationships with other nutrients

facilitates the utilization of (3)

A

iron, calcium, folic acid

34
Q

functions

important antioxidant that protects the body from

A

damaging oxidizing agents

35
Q

functions

formation of _____, the fibrous structural protein in the connective tissues which serves as the matrix on which the bone and teeth are formed

A

collages

36
Q

functions

synthesis of _____, a compound that participates in the transport of fatty acids into mitochondria

A

carnitine

37
Q

functions

hormone and neurotransmitter synthesis (3)

A

steroids, catecholamine, serotonin

38
Q

functions

operated in the metabolism of certain amino acids which may end up being converted to the hormones _____ and _____

A

norepinephrine and thyroxin

39
Q

deficiency

symptoms include petechiae, swelling, infection, bleeding of gums, and muscle pains

other deficiency symptoms include anemia, lower resistance to infection depression, and rough skin

those who do not consume sufficient quantities of fruits and vegetables

smoking (generates free radicals), hence elevated requirements for vitamin c

A

scurvy

40
Q

toxicity

high levels of intake result in
nausea abdominal cramps, diarrhea, fatigue, insomnia, hot flashes, rashes in skin, interference with medical tests, aggravation of gout symptoms, excessive urination and kidney stones

A

-

41
Q

food sources

A

ripe papaya, citrus fruits, raw cabbage, tomatoes, guava, mango, cantaloupes, strawberry, sweet pepper, turnips, potato, and organ meats (liver and kidney)

42
Q

recommended intake for children ages (1-12)

A

45 mg both male and female

43
Q

recommended intake for school-age children and adolescents

A

55-60 mg

44
Q

recommended intake for adolescents, adults, and old age

A

60 for females
70 for males

45
Q

recommended intake for pregnant

A

60 +10

46
Q

recommended intake for lactating

A

60 +35