Define absorption, storage and elimination of cyanocobalamin, Biology

Assignment Help:

Define Absorption, Storage and Elimination of cyanocobalamin?

Vitamin B12 in food is bound to proteins and is only released by the action of a high 'Concentration of hydrochloric acid present in the stomach. Once released from foods, vitamin B12 absorption involves contact with two proteins, intrinsic .factor (IF) and R binder. The glycoprotein, called R-binders (or haptoconins), protect vitamin B12 from chemical denaturation in the stomach, IF is a glycoprotein synthesized by the gastric parietal cells and function in the small intestine.

Although the formation of the vitamin B12- intrinsic factor complex was initially thought to happen in the stomach, it is now clear that this is not the case. At an acidic pH, (in the stomach) the affinity of the intrinsic factor for vitamin B12 is low whereas its affinity for the R-binders is high. When the contents of the stomach enter the duodenum, the R-binders become partly digested by the pancreatic proteases, which in turn cause them to release their vitamin B12. Because the pH in the duodenum is more neutral than that in the stomach, the intrinsic factor has a high binding affinity to vitamin B12, and it quickly binds the vitamin as it is released from the R-binders.  The vitamin B12 intrinsic factor complex then proceeds to the lower end of the small intestine, where it is absorbed by phagocytosis by specific ileal receptor. The absorbed cbl is processed into a complex transcobalamin-II-cbl (TCII-cbl), secreted into portal blood and delivered to the liver and ultinlately all tissues.

Vitamin B12 is the only B vitamin our body can store. The average adult body contains 2 to 5 1ng of vitamin B12 with 80 percent of this stored in the liver.


Related Discussions:- Define absorption, storage and elimination of cyanocobalamin

Composition of cell membrane, COMPOSITION Proteins = 44-76%,  Lipids...

COMPOSITION Proteins = 44-76%,  Lipids = 20-53%,      Carbohydrates = 1-8%,  (Protein-Lipid ratio = 0.8 : 1 to 4 : 1) Most of lipid are "Phospholipids" which are amphipat

What is sex-influenced dominance, What is sex-influenced dominance? The...

What is sex-influenced dominance? The Sex-influenced dominance is the phenomenon in which the manifestation of a phenotype of a gene in heterozygosity depends on the sex of the

What is an antigen, Q. What is an antigen? Antigen is any substance, in...

Q. What is an antigen? Antigen is any substance, infectious or particle agent recognized as foreign to the body. The contact of the antigen with the body promotes a defense rea

Name the ceramics used in bioactive, Bioactive Ceramics:-   Hydroxyapa...

Bioactive Ceramics:-   Hydroxyapatite, Tricalcium phosphate, Tetracalcium phosphate, calcium pyrophosphate. Fluorapatite, brushite,  bioglass.

Systems of classification plants, Q. Can you show the Systems of classifica...

Q. Can you show the Systems of classification plants? The development of angiosperm classification has been one of the most fascinating subject. A study of sequential events le

CLASSIFICATION, WHY CORALS MAY SOMETIME BE CONFUSED WITH PLANT

WHY CORALS MAY SOMETIME BE CONFUSED WITH PLANT

How does hcl also directly participate in digestion, Besides being fundamen...

Besides being fundamental for the activation of the main gastric digestive enzyme how does HCl also directly participate in digestion? With its corrosive effect, HCl also helps

Explain the factor chromosomal inheritance, Explain the factor Chromosomal ...

Explain the factor Chromosomal Inheritance? A huge step forward in our understanding of heredity came in 1902, when a biologist named Walter S. Sutton proposed that Mendel's "f

Explain the economic and social burden of heart diseases, Explain the Econo...

Explain the Economic and Social Burden ? Cardio-vascular diseases pose tremendous economic strain on the population and the countries throughout the world. However there is a d

Handling microorganisms, Handling : You can reduce direct contact with mic...

Handling : You can reduce direct contact with microorganisms by careful handling and by wearing protective clothing such as rubber gloves, mask, lab coat, etc. Even if you entirel

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd