Which of the following statement(s) is/are true about Vitamin $B_{12}$?
a. It is also known as cobalamin.
b. It is composed of cobalt-atom.
c. It consists of corrin ring.
Choose the correct option:

Correct option is C

The correct answer is (c) a, b and c are true statements
Explanation: • Cobalamin (a): Vitamin B12 is chemically known as cobalamin because it contains a metal ion of cobalt at its core. • Cobalt-atom (b): It is the only vitamin that contains a metal ion ( Cobalt, Co). The cobalt atom is held in the center of the molecule, which is essential for its biological activity. • Corrin ring (c): The structure of Vitamin B12 consists of a corrin ring, which is a macrocyclic ligand similar to the porphyrin ring found in hemoglobin (iron) and chlorophyll (magnesium). • It is a water-soluble vitamin that plays a critical role in the formation of red blood cells, cell metabolism, nerve function, and the production of DNA. • Human beings cannot synthesize Vitamin B12; it must be obtained from animal-based foods or fermented products, as it is produced only by certain bacteria and archaea.
Information Booster: • According to NCERT Biology (Class 12), Vitamin B12 is essential for the maturation of erythrocytes (RBCs). Its deficiency leads to Pernicious Anemia. • The absorption of Vitamin B12 in the stomach requires a glycoprotein called Castle's Intrinsic Factor, which is secreted by the parietal cells of the gastric glands.
Additional Knowledge:
Sources of Vitamin B12 • Significant sources include dairy products, eggs, fish, and meat. For vegetarians, curd (Lactobacillus) can be a helpful source because bacteria synthesize the vitamin during the fermentation of milk.
Storage • Unlike most water-soluble vitamins that are excreted quickly, the human body can store Vitamin B12 in the liver for several years.
Industrial Production • Vitamin B12 is produced industrially through bacterial fermentation using species like Pseudomonas denitrificans or Propionibacterium freudenreichii.