Vitamin B12 Flashcards Quizlet Study with quizlet and memorize flashcards containing terms like what is another name for b12?, what b12 structurally similar to?, what are the two present biologically active forms? and more. scheduled maintenance: july 8, 2024 from 07:00 pm to 09:00 pm. Know the steps involved in vitamin b12 digestion and absorption. 1. ingest b12. 2. gastric proteases and hcl cleave b12 from proteins (usually bound in animal proteins) so it can be free. 3. saliva and gastric cells produce r proteins, which protect the acid sensitive b12 as it moves though the stomach so it doesn't react with anything else or.
Vitamin B12 Flashcards Quizlet The if b12 complex is split apart in the lysosomes and then binds to transcobalamin (transfer protein) and is transported to cells. the vitamin b12 is then taken up by endocytosis receptors into cells or taken to the liver for storage or reabsorbed by the kidneys. why does it take years to develop a deficiency of this vitamin even though it is. Vitamin b12 is a water soluble vitamin, so any unused amount will exit the body through the urine. generally, up to 1000 mcg a day of an oral tablet to treat a deficiency is considered safe. the institute of medicine states “no adverse effects have been associated with excess vitamin b12 intake from food and supplements in healthy individuals.”. Describe different routes of vitamin b12 excretion. note: daily losses of b12 are ~0.1% of the total body b12 pool. therefore, b12 deficiency can take years to develop. urine: kidneys reabsorb a large proportion of b12 due to high density of tc receptors (hence little b12 in urine) fecal loss: considerable clearance of haptocorrin b12 in bile from the liver enterohepatic circulation of b12. B12 absorption. intrinsic factor mediated absorption 1. intrinsic factor is synthesized in the stomach 2. b12 combines with r protein in stomach and travels to small intestine 3. b12 releases r protein and complexes with if4. b12 if is absorbed in the ileum 5. b12 is released once complex is in the enterocyte.
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