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1 BIOLOGY MCQS

Which of the following contains cobalt?

  • Vitamin K
  • Chlorophyll
  • Vitamin B12
  • Haemoglobin
Correct Answer: C. Vitamin B12

Detailed Explanation

Cobalt is a trace mineral that plays an important role in human health, but it is not present freely in the body in large amounts. Instead, it is found as a central atom in Vitamin B12, also known as cobalamin. This makes Vitamin B12 the only vitamin that naturally contains cobalt.


Vitamin B12 and Cobalt


Vitamin B12 is a water-soluble vitamin essential for:




  • Formation of red blood cells (RBCs)




  • DNA synthesis




  • Normal functioning of the nervous system




  • Metabolism of fats and proteins




The cobalt atom in Vitamin B12 is part of a complex structure called the corrin ring, which is similar to the porphyrin ring of hemoglobin but contains cobalt instead of iron. Because of this, Vitamin B12 is also referred to as a cobalamin (cobalt-containing compound).


Why Other Options Are Incorrect




  • Vitamin K (Option A): Important for blood clotting, but does not contain cobalt.




  • Chlorophyll (Option B): The green pigment in plants contains magnesium as its central atom, not cobalt.




  • Haemoglobin (Option D): The red pigment in human blood contains iron (Fe) at its core, not cobalt.




Sources of Vitamin B12


Vitamin B12 is mainly found in animal-based foods, such as:




  • Meat (beef, liver)




  • Fish and poultry




  • Eggs and dairy products




  • Fortified cereals




Vegetarians and vegans are at higher risk of Vitamin B12 deficiency, which can lead to anemia, fatigue, and neurological problems.


Key Facts




  • Cobalt in Vitamin B12 is essential for maintaining healthy nerve cells and blood cells.




  • Daily requirement of Vitamin B12 for adults is about 2.4 micrograms.




  • Deficiency may cause pernicious anemia and cognitive issues.




 

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