MODULE 2: B6, B9, B12 Flashcards Preview

VITAMINS & MINERALS > MODULE 2: B6, B9, B12 > Flashcards

Flashcards in MODULE 2: B6, B9, B12 Deck (47)
Loading flashcards...
1
Q

Folate is?

A

B9

2
Q

Cobalamin is?

A

B12

3
Q

Pyridoxine is?

A

B6

4
Q

Pantothenic acid is?

A

B5

5
Q

Thiamin is?

A

B1

6
Q

Riboflavin is?

A

B2

7
Q

Niacin is?

A

B3

8
Q

** Know what the 4 D’s stand for? Vitamin Associated

A

Dementia
Dermatitis
Diarrhea
Death

Niacin! (B3)

9
Q

Biotin is?

A

B7

10
Q

** Know what pellegra is; what B vitamins might be associated

A

Pellegra is SEVERE B3 deficiency - presents as 4 D’s

B6 deficiency might also present with Pellegra

11
Q

** Fate of homocysteine in methylation pathway (what vitamins involved?)

A

B6! = Homocysteine —> Cystathionine —> Cysteine

B12! = Homocysteine —> Methionine (using methionine synthase) + folate

12
Q

Zinc and folate absorption

A

Zinc deficiency INHIBITS folate (B9) absorption

13
Q

** Regulation of sodium channels and ACH receptors involves what B vit?

A

Thiamin/B1

14
Q

** T/F there is more folate in RBCs than is plasma

A

T

15
Q

**FUNCTION OF FOLATE

A

Facilitates the transfer of one carbon-groups from one bio molecule to another

16
Q

** Why is SAMe important? (Function)

A

Important methylating compound (produced by methionine in methylation pathway)

** PRINCIPAL BIOLOGICAL METHYL DONOR

17
Q

** Cysteine, glutamine, and glycine are used to produce?? (Hint: antioxidant)

A

GLUTATHIONE

18
Q

** Vitamin B12 & Intrinsic Factor relationship

A

B12 must BIND with IF in order to be absorbed in the small intestine

(Forms a complex and complex binds to receptors in intestinal enterocytes)

19
Q

** Describe absorption of B12/where it takes place

A
  1. B12 released from food
  2. Binds to R proteins (found in gastric juice)
  3. R protein brings B12 to small intestine
  4. B12 binds with INTRINSIC FACTOR (in upper intestine)
  5. B12-IF complex binds to enterocyte receptors and B12 is absorbed in **DISTAL small intestine
20
Q

** Know B vitamin involved in Pernicious Anemia

A

B12

21
Q

** Where is B12 primarily stored in the body?

A

LIVER

22
Q

** Conversion of homocysteine to methionine requires ?

A

B12

23
Q

** Metabolism of vitamin B6 to the primary coenzyme form, PLP (pyridoxal phosphate), requires ??

A

RIBOFLAVIN

24
Q

** Lethargy, depression, hallucinations, muscle pain, scaly/red dermatitis is seen with deficiency in?

A

BIOTIN (B7)

25
Q

** Fatty acid and cholesterol synthesis - know B vitamin involved

A

NIACIN

26
Q

** What 3 B vitamins are needed to synthesize fatty acids?

A

Niacin (B3)
Riboflavin (B2)
Pantothenic Acid (B5)

27
Q

** B vitamin involved in pernicious anemia?

A

B12 (caused by not enough IF)

28
Q

** Niacin & toxicity?

A

Tolerable Upper Limit because of VASODILATORY EFFECTS

Those with HYPERLIPIDEMIA should avoid/be careful

29
Q

** Niacin toxicity includes

A
SKIN FLUSHING 
Rapid heart beat 
Dizziness 
GI distress (nausea, abdominal pain) 
Itching
Headache
30
Q

** Niacin can be synthesized in the body from?

A

Tryptophan

31
Q

** Niacin’s use in cholesterol treatment? Blood sugar? Metabolic syndrome?

A

Niacin: Used to treat high cholesterol (Lower LDL, raise HDL, lower triglycerides)

May not be useful as it is also associated with inducing insulin resistance/affecting glucose homeostasis and therefore exacerbating metabolic syndrome

32
Q

** Niacin function in fatty acid/cholesterol synthesis?

A

Niacin AS NADPH acts as a reducing agent in F.A./cholesterol synthesis

33
Q

** Hexose Monophosphate shunt is????

A

Pentose Phosphate pathway

34
Q

** Niacin’s relationship to Hexose Monophosphate shunt?

A

NADPH (Niacin/nicotinamide) produced via the Hexose Monophosphate shunt/Pentose-Phosphate pathway

35
Q

** B12 testing?

A

Serum B12

** Methylmalonic acid urine test (If MMA high, B12 low)

36
Q

** B12 deficiency symptoms include:

A
    • Megaloblastic, macrocytic anemia
  • Fatigue, pale skin
  • Shortness of breath
  • Heart palpitations

Neurological

  • Numbness in extremities
  • Poor coordination
  • Abnormal gait
  • Memory loss
  • Psychosis
  • Dementia
37
Q

** RDA for folic acid in women of childbearing age

A

400 micrograms

38
Q

** Relationship between folic acid and B12 deficiency

A

Consuming high amounts of folate can MASK B12 deficiency

39
Q

** Digestive enzymes relationship to FOLATE

A

Folic acid digestion requires CONJUGASE and other enzymes in order to be broken down and absorbed

** Go from poluglutamate form in food —> monoglutamate (to be absorbed)

40
Q

** Best way for accessing long term folate levels?

A

FIGLU excretion

Homocysteine levels! (Elevated H means low B9/12)

41
Q

** What enzyme is the drug methotrexate designed to inhibit?

A

Inhibits DIHYDROFOLATE REDUCTASE which converts DHF to Tetra hydrofolate

42
Q

** Methyl-Folate Trap hypothesis

A

Involves SYNERGISTIC RELATIONSHIP b/t B9 & B12

(During synthesis of methionine from homocysteine) adequate B12 is require to transfer methyl group to folate

If not enough B12, folate gets “trapped” in unusually form/form needed for DNA synthesis THEREFORE DNA synthesis cannot be accomplished

43
Q

** What vitamin is required to activate B6?

A

Riboflavin (B2)

44
Q

** Elevated homocysteine means what for B6/9/12?

A

Elevated H = deficiency B6/9/12

45
Q

** Folate’s function in dividing cells during growth

A

THF (tetrahydrofolate) involved in DNA synthesis/cell division —> promotes proliferation of all cells (good and bad)

46
Q

** Tetrahydrofolate and cancer/dividing cells

A

THF involved in cells division/proliferation/DNA synthesis —> THF sometimes blocked in anti-cancer drugs because THF PROMOTES CELLS PROLIFERATION/GROWTH

47
Q

** Absorption of folate from green (leafy) vegetables (eg. FOLATE IN FOOD)

A

Dietary folate (veggies) require digestion in order to be absorbed

Digestion occurs via ENZYMES (Conjugases/carboxypeptidases in brush border)

  • Brush border enzymes require ZINC & ADEQUATE pH