FNDH 400 Exam 4 Questions and Answers (Verified
Answers)
1-Carbon Metabolism
Focused on the metabolism, or movement, of methyl groups
Specifically single carbon, primarily -CH3 groups
Folic Acid
Synthetic
Monoglutamate
Oxidized form
Stable
Folate
Natural
Reduced form
Contains multiple glutamates in tail
Heat and light sensitive
True or False -- Prior to uptake, glutamates will be cleaved off of folic acid to form
the monoglutamate form
False -- glutamates will be cleaved off of folate not folic acid
Functions of folate/folic acid
Amino acid metabolism
DNA base synthesis
Donates a methyl group to cobalamin forming methyl-cobalamin
Folate Deficiency
-Macrocytic, megaloblastic anemia
-Large nucleated red blood cells
-Improper red blood cell division
True or False -- Spina bifida is the most common neural tube defect that results
from failure of the neural tube to close properly.
True
Which of the following is not a reason why the United States fortifies cereals,
grains and some corn masa flour with folic acid?
To benefit others (men, elderly etc.) who are not women of child-bearing age -- it is
meant to focus specifically on women of childbearing age
B12
, -Spirulina and fermented soy products are NOT reliable sources
-Nutritional yeast and fortified soy milk are good sources of B12 for vegetarians/vegans
-Animals consume B12 produced by microorganisms within soil or it is produced by
microorganisms in their GI tracts
-It is found almost exclusively in animal products
Vitamin B12's scientific name
Cobalamin-- contains cobalt and many amine groups
Do dietary cobalamins equivalents exist?
No bc the different cobalamins have similar bioavailibility
2 Cofactor forms of cobalamin
-Adenosylcobalamin
-Methylcobalamin
Most common form of cobalamin found in supplements
cyanocobalamin, with some also using methylcobalamin
Cyanocobalamin
Synthetic form of vitamin B12
Hapatocorrin
Salivary glands
released by salivary glands before being degraded by proteases in the small intestine.
Intrinsic Factor
Stomach
is produced in the stomach, but binds to B12 in the duodenum.
Transcobalamin 2
Enterocyte
binds to B12 after intrinsic factor is broken down in the enterocyte after uptake.
True or False -- Intrinsic factor is of particular importance to vitamin B12
absorption because uptake into the enterocyte happens through intrinsic factor
+B12 binding to cubulin.
True
Intrinsic factor is extremely important because of its role in vitamin B12 uptake into the
enterocyte.
Function of Vitamin B12
-Cofactor methionine synthase
-Cofactor for enzyme that breaks down odd chain fatty acids
-Involved in donating methyl group to homocysteine
-Important for maintaining the myelin sheath
2 symptoms of B12 deficiency
-Megaloblastic (Macrocytic) Anemia
-Neurological abnormalities
Megaloblastic (Macrocytic) Anemia
-Symptom of B12 deficiency
-Same anemia that occurs in folate deficiency
Answers)
1-Carbon Metabolism
Focused on the metabolism, or movement, of methyl groups
Specifically single carbon, primarily -CH3 groups
Folic Acid
Synthetic
Monoglutamate
Oxidized form
Stable
Folate
Natural
Reduced form
Contains multiple glutamates in tail
Heat and light sensitive
True or False -- Prior to uptake, glutamates will be cleaved off of folic acid to form
the monoglutamate form
False -- glutamates will be cleaved off of folate not folic acid
Functions of folate/folic acid
Amino acid metabolism
DNA base synthesis
Donates a methyl group to cobalamin forming methyl-cobalamin
Folate Deficiency
-Macrocytic, megaloblastic anemia
-Large nucleated red blood cells
-Improper red blood cell division
True or False -- Spina bifida is the most common neural tube defect that results
from failure of the neural tube to close properly.
True
Which of the following is not a reason why the United States fortifies cereals,
grains and some corn masa flour with folic acid?
To benefit others (men, elderly etc.) who are not women of child-bearing age -- it is
meant to focus specifically on women of childbearing age
B12
, -Spirulina and fermented soy products are NOT reliable sources
-Nutritional yeast and fortified soy milk are good sources of B12 for vegetarians/vegans
-Animals consume B12 produced by microorganisms within soil or it is produced by
microorganisms in their GI tracts
-It is found almost exclusively in animal products
Vitamin B12's scientific name
Cobalamin-- contains cobalt and many amine groups
Do dietary cobalamins equivalents exist?
No bc the different cobalamins have similar bioavailibility
2 Cofactor forms of cobalamin
-Adenosylcobalamin
-Methylcobalamin
Most common form of cobalamin found in supplements
cyanocobalamin, with some also using methylcobalamin
Cyanocobalamin
Synthetic form of vitamin B12
Hapatocorrin
Salivary glands
released by salivary glands before being degraded by proteases in the small intestine.
Intrinsic Factor
Stomach
is produced in the stomach, but binds to B12 in the duodenum.
Transcobalamin 2
Enterocyte
binds to B12 after intrinsic factor is broken down in the enterocyte after uptake.
True or False -- Intrinsic factor is of particular importance to vitamin B12
absorption because uptake into the enterocyte happens through intrinsic factor
+B12 binding to cubulin.
True
Intrinsic factor is extremely important because of its role in vitamin B12 uptake into the
enterocyte.
Function of Vitamin B12
-Cofactor methionine synthase
-Cofactor for enzyme that breaks down odd chain fatty acids
-Involved in donating methyl group to homocysteine
-Important for maintaining the myelin sheath
2 symptoms of B12 deficiency
-Megaloblastic (Macrocytic) Anemia
-Neurological abnormalities
Megaloblastic (Macrocytic) Anemia
-Symptom of B12 deficiency
-Same anemia that occurs in folate deficiency
