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NS Preliminary Exam 2 > Water-soluble Vitamins > Flashcards

Water-soluble Vitamins Flashcards

1
Q

Which vitamin acts as an electron carrier during glycolysis (glucose to pyruvate), from pyruvate to lactic acid, and during the Krebs cycle?

A

Niacin (vit B3)

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2
Q

Which vitamin is required for the formation of acetyl CoA from pyruvate?

A

Thiamin (B1)

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3
Q

Which vitamin is a component of CoA?

A

Pantothenic Acid (B5)

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4
Q

During what phases does Niacin (vit B3) act as an electron carrier? What is the other vitamin involved in the Krebs cycle phase of electron transport?

A

glycolysis (glucose to pyruvate), from pyruvate to lactic acid, and the Krebs cycle. Flavin (vit b2)

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5
Q

Which two vitamins are involved in the Krebs cycle phase of electron transport?

A

Flavin (vit b2) and Niacin (vit b3)

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6
Q

Name all the B vitamins we learned about

A

B1 (thiamin), B2 (riboflavin), B3 (Niacin), and B5 (Pantothenic acid)

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7
Q

What is the primary function of B vitamins?

A

To act as coenzymes in energy metabolism (they dock with the enzymes to make reactant molecules attracted to the enzyme docking site.)

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8
Q

Are vitamins an energy source? Are they needed in large or small amounts?

A

They are not an energy source. They’re needed in small amounts.

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9
Q

What are the water-soluble vitamins?

A

The B vitamins (B1-thiamin, B2-riboflavin, B3-niacin, B5-pantothenic acid) and Vitamin C.

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10
Q

How are B and C vitamins absorbed?

A

Through the bloodstream (not the lymphatic system): they’re water-soluble.

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11
Q

Are water-soluble vitamins vulnerable to cooking losses?

A

Yes

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12
Q

What is beriberi and what vitamin is missing in this condition?

A

Beriberi is a polyneuritis disease: affects the peripheral nervous system, and is characterized by edema, weakness, loss of feeling in the legs, heart failure, and breathlessness. It is a result of lack of thiamine (Vit B1).

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13
Q

Who was involved in the discovery of Thiamin (B1)? (4 people) What do you know about their experiments?

A

Pekelharing (dogs), Eijkman (chickens), Vorderman (prisions in Java, 1897), Funk (pigeons, 1911). Pekelharing injected blood from beriberi patients into dogs, who over time with consistent injections, died. Eijkman picked up this experiment with chickens. The ones fed polished military rice in the first round died, the ones fed brown rice did not. Vorderman did an observational study of prisoners in Java fed white rice or brown rice who developed beriberi. Funk fed white rice to pigeons and cured them of head retraction with yeast extract.

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14
Q

What does thiamin (b1) do?

A
  • Required for the formation of acetyl CoA from pyruvate.
  • B1 is a coenzyme in energy metabolism (part of coenzyme thiamin pyrophosphate-TPP)
  • TPP helps break down glucose, helps make RNA and DNA, and helps to power protein synthesis
  • TPP helps to synthesize and regulate neurotransmitters
  • TPP regulates membrane chloride channels in nerve cells
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15
Q

What happens with a deficiency of B1 (thiamin)? (mild and severe) (3 outcomes)

A

-mild: headache (nerves), irritability (nerves), depression, loss of appetite (vagus nerve…?)
-severe: beriberi: profound muscle weakness and nerve destruction
two kinds of beriberi: wet and dry
-wernicke-korsakoff syndrome: loss of recent memory, confabulation (making up stories), and hallucinations. associated with chronic alcoholism.

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16
Q

Name of B1

A

thiamin

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17
Q

Which vitamin is thiamin?

A

Vitamin B1

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18
Q

What are the two kinds of beriberi and what do they do?

A

Wet beriberi: involves the heart and leads to edema of lower extremities
dry beriberi: peripheral neuritis

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19
Q

Why can alcoholism cause vitamin deficiencies?

A
  • alcohol contributes calories without nutrients.
  • alcohol interferes with vitamins (B vits 1, 2, 3, 6, 7, 9)
  • chronic alcohol use leads to inhibition of the entry of thiamin into the body via the small intestine
  • it also inhibits reabsorption of thiamin in the kidneys
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20
Q

What does raw fish, blueberries, tea leaves and red beetroot and cabbage do to thiamin (B1)?

A

They destroy thiamin.

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21
Q

What happens with excess of thiamin?

A

Nothing: no reports of thiamin toxicity.

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22
Q

Where is thiamin from the diet absorbed? Where is thiamin from microflora absorbed?

A

Small intestine; colon.

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23
Q

What are purified diets? Who developed them?

A

Contain only the macronutrients: proteins, carbs and fats, and minerals. developed by Elmer McCollum

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24
Q

Who discovered riboflavin (vit b2)?

A

Paul Gyorgy (and a little McCollum w the purified diets)

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25
Q

What does riboflavin (vit b2) do?

A
  • key role in reactions to metabolize fats, carbs and proteins (deamination)
  • converts folic acid and vit b6 into their active coenzyme form
  • supports antioxidants
  • electron carrier in citric acid cycle: FAD/FADH2
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26
Q

Which electron carriers are vit b2 (riboflavin) involved in?

A

FAD to FADH2

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27
Q

What happens with riboflavin/vit b2 deficiency (rare…sometimes with alcoholism and mutations in transporter)?

A
  • skin disorders (first show around the mouth and tongue…cracked, shiny, inflamed)
  • anemia: because of link to pyridoxine (b6) and folate (b9)
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28
Q

sources of riboflavin (b2):

A
  • seaweed
  • beef liver
  • soybeans
  • almonds
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29
Q

What happens when you eat too much riboflavin (b2)?

A

nothing: no reported toxicity

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30
Q

Where is dietary riboflavin absorbed? riboflavin from microflora?

A

small intestine. colon.

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31
Q

How can riboflavin be destroyed?

A

Sunlight.

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32
Q

Who discovered niacin (vit b3)?

A

Joseph Goldberger (pellagra guy who ate people’s poop to show it wasn’t infectious)

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33
Q

Functions of niacin (vit b3):

A
  • coenzyme in energy metabolism in mitochondria (think b2 helps break down macronutrients, b3 gets energy from those macronutrients)
  • electron transport in glycolysis, citric acid cycle and electron transport chain
  • supports fatty acid synthesis
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34
Q

Which vitamin is niacin?

A

Vitamin b3

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35
Q

Which vitamin is riboflavin?

A

Vitamin B2

36
Q

How is vitamin B3 (niacin) deficiency caused?

A

Poor diet, alcoholism and transporter mutation.

37
Q

What are the symptoms of severe pellagra, and what deficiency is this caused by?

A 
Vit B3 (niacin).
-4 Ds: dermatitis, diarrhea, dementia and death (v-shaped lesions around neck and swelling of body)
38
Q

mild symptoms of vit b3 (niacin) deficiency:

A

-tiredness, weakness, inability to concentrate, poor memory

39
Q

What happens with large doses of niacin?

A
  • Good effect: raises HDLC and lowers triglycerides

- Bad effect: if used chronically, flushes skin, itching, and GI and liver disorders

40
Q

Sources of niacin (vit b3):

A
  • turkey breast, #1 (conversion of tryptophan to niacin)
  • salmon
  • peanuts
  • tuna
41
Q

Where is dietary niacin absorbed? What are endogenous sources?

A
  • in the small intestine and partly in the stomach

- tryptophan converted to niacin

42
Q

Who discovered pantothenic acid (b5)? What year? What do you know about it?

A

Roger Williams (1931).

  • acidic substance needed to grown some yeasts
  • pantothenic: from everywhere
43
Q

Functions of b5 (pantothenic acid):

A
  • component of coenzyme A (CoA) and acyl carrier protein:

- both needed for macronutrient metabolism

44
Q

What happens with b5 deficiency? What else about this?

A
  • things related to not enough sugar or macronutrients: low blood sugar, fatigue, irritability, muscle cramps, digestive disturbance
  • this never happens in actual humans because b5 comes from everywhere (only found in labs)
45
Q

How is pantothenic acid (b5) damaged?

A

Freezing, canning, processing and refining grains

46
Q

Which transporter does b5 share?

A

b7 transporter

47
Q

Exogenous and endogenous sources of b5?

A

Diet (lots of foods) and colonic microflora.

48
Q

Which vitamins are involved in amino acid metabolism, and what do they do? What diseases do this help to prevent?

A

Flavin (B2) and cobalamin (b12) turn the amino acid homocysteine into the AA methionine, which helps with DNA methylation to control gene expression. Choline also does this through another pathway. Vit b6 (pyridoxine) turns homocysteine into cysteine. Pyridoxine also helps to turn vit b9 (folate) into DNA. High amounts of homocysteine indicated a low level of b vitamins because it’s not being turned into methionine and cysteine, and high levels of homocysteine can lead to cardiovascular disease, diabetes and cancer.

49
Q

Functions of b6 (pyridoxine)

A
  • coenzyme in amino acid and protein metabolism, which has an impact on DNA synthesis (one of first places this affects if not synthesized is anemia)
  • lowers blood levels of homosysteine
  • synthesis of neurotransmitters (serotonin, dopamine, etc)
  • supports immune system
50
Q

discovery of b6

A

paul gyorgy w rats on a semisythetic diet plus vit b1 and riboflavin. rat started getting all flaky and gross: lesions, edema, redness, scaly skin: acrodynia

51
Q

what did paul gyorgy find b6 prevent and could cure?

A

acrodynia (the rats), epileptiform convulsions, and microcytic anemia (red blood cells get small and misshapen due to problems with dna synthesis)

52
Q

what did paul gyorgy find b6 prevent and could cure in rats?

A

acrodynia (the rats), epileptiform convulsions, and microcytic anemia (red blood cells get small and misshapen due to problems with dna synthesis)

53
Q

What causes b6 (pyridoxine) deficiency, and how does it affect people?

A

causes:
-malnutrition
-chronic alcoholism
-impaired transport
-celiac disease
effects:
-neurological disorders (think synthesis of neurotransmitters like serotonin)
-seizures in the young (think epileptic rats)
-anemia (because of DNA synthesis)

54
Q

What happens with excess of b6 (pyridoxine)?

A
  • neurological damage (decreased sensation to touch, temp and vibration, poor coordination)
  • GI symptoms (upset stomach, nausea, heartburn)
  • sleepiness
  • headache
55
Q

What happens with excess of b6 (pyridoxine)?

A
  • neurological damage (decreased sensation to touch, temp and vibration, poor coordination)
  • GI symptoms (upset stomach, nausea, heartburn)
  • sleepiness
  • headache
56
Q

discovery of b7 (biotin)

A
  1. egg white injury: rats fed egg whites developed dermatitis, lost hair, spastic gait. raw liver and yeast cured it. paul gyorgy again (b6), this time with vincent de vigneaud: called it vit H for skin in german.
57
Q

functions of b7 (biotin)

A

coenzyme in metabolic reactions (think fats good for skin):

  • catabolism of certain amino and fatty acids
  • fatty acid biosynthesis
  • gluconeogenesis (new glucose from fats and proteins)

regulates gene expression by influencing transcription (required for expression of thiamin transporter)

58
Q

biotin (b7) deficiency causes and effects

A

causes:

  • chronic alcoholism
  • too many raw eggs…
  • inflammatory bowel disease

effects:

  • neurological disorders
  • dermatitis around body orifices
  • alopecia (hair loss)
  • conjunctivitis
  • deficiency during pregnancy can lead to congenital malformation (heart) and death
59
Q

What happens with excess of b7 (biotin)?

A

nothin

60
Q

What happens with excess of b7 (biotin)?

A

nothin

61
Q

food sources of biotin (b7):

A

widely distributed in dairy, meat (liver), and vegetables

62
Q

food sources of biotin (b7):

exogenous?

A

widely distributed in dairy, meat (liver), and vegetables. colonic bacteria.

63
Q

tell me about biotin absorption

A

happens in the small and large intestine through transport mechanisms shared with pantothenic acid (b5, also from a lot of dietary sources).

64
Q

discovery of folate (b9)

A

Lucy Wills in India looking at pernicious anemia in prego women. Women who were rich weren’t getting it, so it was nutritional. When they ate liver and marmite they got better, increasing RBC count.

65
Q

Functions of b9 (folate):

A
  • coenzyme in DNA synthesis and cell division
  • needed for normal red blood cell synthesis
  • reduces neural tube defects
66
Q

B9 (folate) deficiency causes and effects:

A

causes:
- mutations to transporter (PCTF) system
- celiac disease
- chronic alcoholism

effects:
- spina bifida
- anemia (megaloblastic, also from b12), diahrrea
- birth defects
- heart disease
- cancer

67
Q

What happens with excess of b9 (folate)?

A
  • can mask b12 deficiency (folate is regenerated by b12)

- hypersensitive people might get hives or respiratory stress

68
Q

where is folate absorbed? endogenous and exogenous sources?

A

Dietary folate absorbed in small intestine. folate from large intestine microflora absorbed in the colon.

69
Q

discovery of b12 (cobalamin)

A

Mary shorb and Folkers. There were no good animal models to study it. Shorb discovered bacteria that responded to liver. The two of them then joined up and Folkers isolated the red crystals (b12) that the bacteria were responding to.

70
Q

Functions of cobalamin (b12):

A
  • key growth factor (led to increased yields for livestock farmers)
  • coenzyme for amino acid metabolism (metabolizes homocysteine)
  • DNA and red blood cell synthesis (needed for folate function… turns inactive b9 into active)
  • maintain myelin sheath around nerves
71
Q

B12 deficiency causes and effects:

A

Causes:

  • veganism
  • intrinsic factor deficiency (ie from total gastrectomy)

effects:
- megaloblastic anemia (caused by b12 and b9 deficiency)
- severe (possibly permanent) mental disturbances (lack of myelin sheath)

72
Q

How is b12 absorbed (whole process)?

A

The salivary gland produces protein haptocorrin (r protein), which binds to cobalamin to protect it against the low pH in the stomach. Intrinsic factor is produced in the stomach from stomach cells. Pancreatic enzymes in the SI partially degrade haptocorrin, which releases cobalamin to bind with the intrinsic factor. In the ilium, the IF-cobalamin complex binds to a receptor in the small intestine, which allows it to be absorbed. B12 enters circulation bound to transcobalamin (transport protein).

73
Q

What happens with excess of b12 (cobalamin)?

A

nothin

74
Q

Discovery of vitamin c (ascorbic acid):

A

Albert Szent-Gyorgi: purification from orange and lemon juice was difficult. was able to do it when wifey served him fresh paprika. i guess he experimented on guinea pigs with boiled food.

75
Q

Functions of vitamin C:

A
  • antioxidant
  • acts as a cofactor in various metabolic reactions
  • makes other essential compounds
  • enhances iron absorption from plant foods
  • collagen synthesis
  • facilitates conversion of dopamine to neuroepinephrine in adrenal medulla
76
Q

What is collagen?

A

The body’s major building protein: essential to the proper functioning of all major internal organs. important protein to maintain capillaries.

77
Q

Causes and effects of ascorbic acid (vit c) deficiency:

A

causes:
- lack of fresh fruits and veggies

effects:
- scurrrvyyyy (pirates dying and shit)
- lethargy, joints ache, limbs swell, skin bruises like a peach!
- spongy gums, bad breath, teeth loosen, death by hemorrhaging
- poor growth in children

78
Q

Endogenous and exogenous sources? absorption?

A

Comes from diet. No bacterial production. absorbed in small intestine.

79
Q

How does vitamin C get degraded or destroyed?

A

Food processing, exposure to air, drying, salting, cooking.

80
Q

In what population did ascorbic acid decrease instances of common cold by 50%?

A

athletes and soldiers (high stress)

81
Q

Which of the following water-soluble vitamins are
most likely associated with loose stools, forgetfulness
and skin rashes?

A

niacin (DDD: diarrhea, dementia and dermatitis)

82
Q

Discovery of choline:

A
  1. theodore gobley and adolph strecker. came from boiling the lecithin extracted from bile (and brains and carp fish eggs)
83
Q

Functions of choline:

A
  • water-soluble nutrient that maintains lipid structures, and regulates genes and amino acid metabolism
  • used for synthesis of neurotransmitter acetylcholine
  • regulates memory, mood and intelligence
  • phospholipids containing choline (like phosphatidylcholine) are components of plasma and other organelle membranes
  • phosphatidylcholine also required for assembly/secretion of lipoproteins
  • turns homocysteine into methionine…methionine responsible for regulating DNA methylation, which controls for gene expression
84
Q

causes and effects of lack of choline:

A

causes:
- dietary?

effects:
- if choline isn’t provided in first 1000 days after conception, could cause serious permanent brain function deficits
- higher intake associated with lower instances of nonalcoholic fatty liver (think homocysteine to methionine, hc oxidizing ldl, etc)

85
Q

What happens with excess of choline?

A

diarrhea, falling blood pressure, fishy body odor

NS Preliminary Exam 2 (4 decks)

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