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42 Cards in this Set

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A,D,E,K
vitamin class
fat soluble vitamins
characteristics of folic acid
water sol
cofactor for enzymes in aa and nucleotide metabolism
neural tube defects
active form of folic acid
THF
folic acid that can't return to THF without help
5-methyl-THF
requires B12 and reductase (MTHFR)
source of carbon for metylation reactions
serine
THF metabolism gets what byproducts
5 methyl THF for homocysteine met
N10 formyl THF for purine synth
converts dUMP to dTMP for DNA for R & WBCs (on the way back to DHF)
hallmark of folate def anemia
macrocytic (b/c low DNA), normochromic
end product of Homocysteine metab
methionine
for methylation rxns
nec for SAM
end product of methionine metab
homocysteine
methionine to
SAM to
SAH to
homcysteine and adenosine- H causes problems (need B12 & folate to rid)
vitamines required for homocysteine removal
folate & B12 (cobalamine)
or B6
cobalamine is what vit
B12
enzyme for homocysteine removal with folate & B12
methionine synthatase
pathways using SAM
(all produce homocysteine)
NE to epi
guanidinoacetate to creatine
nucleotides to methylated Ntds
Phosphatidylethanolamine to phosphatidylcholine
acetylserotonin to melatonin
pathways for removing homocysteine
folate &B12- methionine synthatase- to methionine

transsulfuration pathway- cystathionine synthase & B6- cystathionine to cysteine
2
baby w/dislocated eye lens, osteoporosis, MR, spontanous blood clots

Dies in 20s w/heart dz
cystathionine synthase def
toxic effects of elevated homocysteine
pre-eclampsia (I risk factor)
endo damage
oxidation of chol
modification apolipos
plt adhes & aggregat
savenge NO (vasoconstriction)
source for folate
green leafies, fruit & liver
primary cause of folate deficiency
dietary intake
secondary causes of folate deficiency
malabsorp (duod)
alch
leukemia & chemo
anticonvulsants
dialysis
premature
dietary requirements for folate
have ~ 3mo supply in body
mostly in liver

need ~ 100-200 micrograms/day
increased need during pregnancy
uptake/absorption of folate
polyglutamate forms in food
hydroxylase at brush border decreases to 1 (can't go past 1)
monoglutamate form into entero
convert to THF & 5 met THF
THF used in cell
MethylTHF into blood w/binding protein
methylenetetrahydrofolate reductase gives...
THF from 5 met THF
deficiency in methylentetrahydrofolate gives...
big risk for pre-eclampsia
assessment of folate levels
need RBC folate concentration
(serum levels not reliable-
variable with intake)
stages of folate deficiency
1- serum levels fall
2- serum & RBC levels low
3- defective EPOesis
4- clinical def= macrocytic, hypochromic anemia
source of B12
only in animal products
(produced by bacteria in animals)

stored in human for 5-10 years

recycled in liver
reactions involving B12
methionine synthetase (clear homocysteine)

methylmalonyl CoA mutase
deficiency in B12 causes
megaloblastic anemia AND neurological deficit
corrin ring
structure of B12
cobalt in center
(cyanocobalamine is supplement)
R proteins
glycoprotein (from mucus cell)

in saliva for cobalamine digestion

need acid to remove B12 from food
Intrinsic Factor necessary for
B12 absorption
TC II
transcobalamine II

takes B12 to tissues (from ileum)

marker for B12 activity (only avail when nec)
B12 is absorbed at...
only terminal ileum, with IF
increased homocysteine AND increased methylmalonic acid
B12 deficiency
increased homocysteine levels only
folate deficiency
form of B12 in blood
methylcobalamine

(for clearing homocysteine)
form of B12 in tissues
adenosylcobalamine
(for clearing branched aas & odd chain FAs - go to succinyl CoA)
methylmalonyl CoA mutase
requires ado-B12
clears branched chain aas (methionine, valine, isoleucine) & odd-chain FAs
gives succinyl CoA
causes of B12 def
strict veg diet
achlorhydia (low stom acid)
panc insuff
pernicious anemia
Ab to IF
TC II defect
lack of IF causes
pernicious anemia
dx of pernicious anemia
Schillings test
Schillings test
dx pernicious anemia
saturate tissues w/B12
radiolabeled B12
24 hr urine to check % cleared
<10% = pernicious anemia