Chapter 9: Vitamin B12 (Cobalamin) Flashcards by isabelle _

Q

other names

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

A

cobalamin

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

pernicious anemia is associated with the deficient intake of

A

cobalamin (vitamin b12)

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

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

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

cobalamin - chemistry

only 2 cobalamins are coenzymatically active

A

methyl cobalamin
5’ - deoxyadenosylcobalamin

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

cobalamin - chemistry

the body can convert all other cobalamins into _____ form

A

enzyme

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

cobalamin - chemistry

is the pharmaceutical form of the vitamin used in supplements

A

cyanocobalamin

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

cobalamin - chemistry

stable in

A

heat

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

cobalamin - chemistry

converted into its active form by removing the _____ group

A

cyano

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

cobalamin - absorption, transport, utilization

bound protein must be released before it can be utilized

A

-

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

cobalamin - absorption, transport, utilization

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

A

acid hydrolysis; proteases

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

cobalamin - absorption, transport, utilization

binds to a salivary polypeptide called the

A

r-binder

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

cobalamin - absorption, transport, utilization

digested by the enzyme ______

A

trypsin

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

cobalamin - absorption, transport, utilization

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

A

intrinsic factor

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

cobalamin - absorption, transport, utilization

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

A

calcium ions

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

cobalamin - absorption, transport, utilization

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

A

absorption

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

cobalamin - absorption, transport, utilization

declines with age due to lack of inadequate secretion of _____

A

gastric acid

Q

cobalamin - absorption, transport, utilization

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

A

b6

Q

cobalamin - absorption, transport, utilization

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

A

transcobalamine i, ii, iii

Q

cobalamin - absorption, transport, utilization

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

A

urine

Q

cobalamin - absorption, transport, utilization

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

A

liver and kidney

Q

cobalamin - functions

important in dna synthesis and is needed for _____ and _____

A

cell growth and division

Q

cobalamin - functions

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

A

myelin

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

Q

cobalamin - functions

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

A

folate

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

deficiency

cobalamin mainly induced by intrinsic factor (IF) deficiency

pernicious anemia

cobalamin elderly, alcoholic, gastrectomy patients, vegan

increased risk of vitamin b12 deficiency

cobalamin (b12) - recommended intake for males (children 1-18 y/o)

0.9 to 2.7 ug

cobalamin (b12) - recommended intake for females (children 1 - 18 y/o)

1.0 to 2.4 ug

cobalamin (b12) - recommended intake for males and females (adults 19 - >70 y/o)

2.4 ug

cobalamin (b12) - recommended intake for lactating

2.4 + 0.5

cobalamin (b12) - recommended intake for pregnant

2.4 + 0.2

cobalamin (b12) - recommended intake for more than 10 years of age is _____ ug/day based on the amount needed to maintain adequate hematological status

2.4 ug/day

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

cobalamin common food sources