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NBCD > Chapter 9: Vitamin B12 (Cobalamin) > Flashcards

Chapter 9: Vitamin B12 (Cobalamin) Flashcards

1
Q

other names

cyanocobalamin
anti-pernicious anemia factor
hydroxycobalamin
erythrocyte maturation factor
animal protein factor

A

cobalamin

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2
Q

pernicious anemia is associated with the deficient intake of

A

cobalamin (vitamin b12)

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3
Q

cobalamin - chemistry

this is called _____ because of their corrin nucleus with an atom of cobalt at the center; group attached to the cobalt may vary resulting in the formation of different cobalamin

A

corrinoids

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4
Q

cobalamin - chemistry

only 2 cobalamins are coenzymatically active

A

methyl cobalamin
5’ - deoxyadenosylcobalamin

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5
Q

cobalamin - chemistry

the body can convert all other cobalamins into _____ form

A

enzyme

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6
Q

cobalamin - chemistry

is the pharmaceutical form of the vitamin used in supplements

A

cyanocobalamin

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7
Q

cobalamin - chemistry

stable in

A

heat

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8
Q

cobalamin - chemistry

converted into its active form by removing the _____ group

A

cyano

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9
Q

cobalamin - absorption, transport, utilization

  1. bound protein must be released before it can be utilized
A

-

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10
Q

cobalamin - absorption, transport, utilization

  1. released from this protein complex by _____ in the stomach and the _____ in pancreatic juice
A

acid hydrolysis; proteases

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11
Q

cobalamin - absorption, transport, utilization

  1. binds to a salivary polypeptide called the
A

r-binder

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12
Q

cobalamin - absorption, transport, utilization

  1. digested by the enzyme ______
A

trypsin

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13
Q

cobalamin - absorption, transport, utilization

  1. vitamin b12 combined with the _____ (IF), a glycoprotein secreted in the stomach
A

intrinsic factor

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14
Q

cobalamin - absorption, transport, utilization

  1. cobalamin - if complex travels to the ileum, catalyzed by _____
A

calcium ions

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15
Q

cobalamin - absorption, transport, utilization

  1. absorption rate decrease as one’s intake increases; needs IF for _____
A

absorption

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16
Q

cobalamin - absorption, transport, utilization

  1. declines with age due to lack of inadequate secretion of _____
A

gastric acid

17
Q

cobalamin - absorption, transport, utilization

  1. decreases among individuals with _____ deficiency (condition decreases the release of IF), iron deficiency, hyperthyroidism and gastritis, and those taking anticonvulsants and antibiotics
18
Q

cobalamin - absorption, transport, utilization

  1. b12 goes to the blood and combines with 3 transport proteins called _____, to the liver and bone marrow
A

transcobalamine i, ii, iii

19
Q

cobalamin - absorption, transport, utilization

  1. with sufficient transport proteins, little of the vitamins are lost in the _____, as blood is filtered through the kidney
20
Q

cobalamin - absorption, transport, utilization

  1. stored in great amounts in _____ and _____ as b-12 protein complex, sufficient supply body for 6-10 years
A

liver and kidney

21
Q

cobalamin - functions

important in dna synthesis and is needed for _____ and _____

A

cell growth and division

22
Q

cobalamin - functions

needed in the synthesis of _____, the lipoprotein substance that surrounds the nerve fibers

23
Q

cobalamin - functions

involved in the conversion of malonyl coenzyme a (coa) to _____ that functions in the degradation of propionate from odd-chain fatty acids

A

succinyl coa

24
Q

cobalamin - functions

helps folate coenzyme to participate in dna synthesis by converting _____ to its active form

25
Q

cobalamin

sore tongue, gastrointestinal tract (git) discomfort, coldness of the extremities, and neurologic changes due to the demyelination

A

deficiency

26
Q

cobalamin

mainly induced by intrinsic factor (IF) deficiency

A

pernicious anemia

27
Q

cobalamin

elderly, alcoholic, gastrectomy patients, vegan

A

increased risk of vitamin b12 deficiency

28
Q

cobalamin (b12) - recommended intake

for males (children 1-18 y/o)

A

0.9 to 2.7 ug

29
Q

cobalamin (b12) - recommended intake

for females (children 1 - 18 y/o)

A

1.0 to 2.4 ug

30
Q

cobalamin (b12) - recommended intake

for males and females (adults 19 - >70 y/o)

31
Q

cobalamin (b12) - recommended intake

for lactating

32
Q

cobalamin (b12) - recommended intake

for pregnant

33
Q

cobalamin (b12) - recommended intake

for more than 10 years of age is _____ ug/day based on the amount needed to maintain adequate hematological status

A

2.4 ug/day

34
Q

cobalamin

foods of animal origin: meat, fish, shellfish, poultry, and milk

A

cobalamin common food sources

NBCD (89 decks)

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