Which vitamin requires intrinsic factor for its absorption-

Ans. is 'b' i.e., Cyanocobalamine * Vitamin B12 (cyanocobalamine) is absorbed in the ileum. Intrinsic factor (of castle) is necessary for its absorption. IF is secreted by oxyntic cells of stomach. In the lumen of the small intestine, IF forms a complex with vitamin B12. Vitamin B12-IF complex binds with a specific receptor on the surface of the epithelial cells of the ileum. Vitamin BJ2 is transported into the enterocytes leaving behing IF at the brush border.