Vitamin B12 Flashcards
Vitamin B12 is also called
Cobalamin
Vitamin B12 sources
Liver, Red meat, fish, eggs, dairy products, and cereals
Remethlation of Homocysteine to methionine requires?
Vitamin B12(cobalamin) N5-Methyltetrahdrofolate
Deficiency of Cobalamin causes what type of anemia?
Megaloblastic Anemia
B12 deficiency can be determined by the level of acid in the blood. Name that acid.
Methylmalonic acid
Methylmalonic acid and Propionic acid accumulate in the myelin sheath of neurons. This causes?
Neuropsychiatric symptoms. The CNS effects are irreversible.
Why is Methylmalonic acid level elevated in people with B12 deficiency?
The enzyme (methylmalonyl reductase) responsible for converting methylmalonyl CoA to Succinyl CoA requires B12.
Remethylation of Homocysteine is impaired due to the deficiency of B12. What does high Hyc do?
Elevated Hyc destroys the endothelial lining and damaged endothelial lining causes thrombi formation.
In B12 deficiency, Methionine levels are low or high?
Low
Folate is trapped in the cell in the form of?
N5-methyl-THF
B12 and Folate deficiencies both cause neurological symptoms.
True or False.
False
Only B12 deficiency does.
What test is done to evaluate B12 absorption?
Schilling’s Test
What is Achlorhydria?
Reduction of gastric acid secretions
Pernicious Anemia is caused by
Failure of the gastrointestinal tract to absorb B12
Lack of Intrinsic factor can be caused by
Gastrectomy of Parietal or Total tract.
Treatment of B12 deficiency
Oral supplementation of B12
Intramuscular injections of cyanocobalamin
What are the levels of ALP in pernicious anemia?
Low levels of ALP
Where is Vitamin B12 stored in our body?
Liver
B12 is __________ (released/remain bonded) from food in the acidic environment of the stomach.
Released
In the stomach, free B12 binds a glycoprotein ___________ (Haptocorrin/Intrinsic factor) and moves to the intestine.
Haptocorrin or R-protein
When entered in intestine, pancreatic enzymes break the bond between R-protein and B12 and then B12 bonds to ___________ (Intrinsic factor/cubilin)
Intrinsic factor
Cubilin is the receptors present on cells of ileum.
B12 when enters the general circulation it is transported by ____________ (transcobalamin/cubilin/albumin)
Transcobalamin
