Exam - Vitamin B12 Flashcards
supplement label
helps produce red blood cells
what is another name for Vit B12
cobalamin
what is Vit B12 a generic term for
a group of corrinoids
why are the compounds called corrinoids
they have a corrin nucleus that contains cobalt
what is the most complex vitamin structure
B12 - discovered last because of this
what produced B12
bacteria only
where is B12 present
animal products
who is at risk for a deficiency
vegetarians/vegans
is there a plant provitamin B12
no
what does a B12 deficiency cause
functional folate deficiency
neurological problems
is there an upper limit
no
2 leading causes of Vit B12 deficiency
not enough in diet
improper absorption due to defects in intrinsic factor
how are deficiencies shown in blood
in the form of megaloblastic anemia
where is folate critically important
in dividing cells that support the production of specialized cells that form the neural tube (early pregnancy)
what can folate deficiencies leaf to
severe birth defects i.e neural tube defects
what is the neural tube in embryo
the CNS which becomes the spinal cord or brain
what is a NTD
opening of spinal cord or brain
what are the key players in single carbon metabolism
folate
vitamin B12
S-adenosyl methionine
what can folate deficiency lead to
impaired DNA synthesis and repair
uracil misincorporation
megaloblastic anemia
what is the folate trap when someone is B12 deficient
in single carbon metabolism, there is no SAM cycle because there is no B12 cofactor and N5-methyl THF cannot become THF
what bypasses the folate trap
large doses of folate can hide a B12 deficiency - large doses can form N5-methyl THF in the gut so there is more folate going to liver to be converted into THF
