Which of the following vitamin contain cobalt?

Appeared in: UPPSC 2017

Explanation

Vitamin B₁₂, also known as cobalamin, is unique among vitamins as its chemical structure contains a metal ion.
Specifically, it features a complex corrin ring with a central cobalt atom, which is the origin of its name.
This cobalt atom is essential for its biological functions, including DNA synthesis, red blood cell formation, and maintaining neurological health.

Option A: Vitamin A (retinol) is a fat-soluble vitamin crucial for vision, immune function, and cell growth. Its structure is based on a beta-ionone ring and a polyunsaturated side chain, and it does not contain cobalt.
Option B: Vitamin B₁ (thiamine) is a water-soluble vitamin that acts as a coenzyme in carbohydrate metabolism. Its structure contains a pyrimidine ring and a thiazole ring, but no cobalt.
Option C: Vitamin B₆ (pyridoxine) is a water-soluble vitamin involved in amino acid metabolism, neurotransmitter synthesis, and hemoglobin formation. It does not contain cobalt.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Biochemistry of Vitamins as background academic context rather than a clinical decision trigger.
Nurses must recognize that Vitamin B₁₂ deficiency leads to megaloblastic anemia and potentially irreversible neurological damage, known as subacute combined degeneration of the spinal cord.
Populations at high risk for B₁₂ deficiency include strict vegans (since B₁₂ is found in animal products), the elderly (due to decreased gastric acid and intrinsic factor), and patients who have undergone gastric or ileal resection.
What if? If a patient has pernicious anemia, they lack the intrinsic factor needed to absorb oral B₁₂. In this case, oral supplements are ineffective, and the nurse must administer lifelong parenteral (intramuscular) Vitamin B₁₂ injections.

How to Approach the Question

This is a factual recall question from biochemistry.
First, identify the core of the question: which vitamin is associated with the element 'cobalt'.
Recall the chemical names of the vitamins. The name 'cobalamin' for Vitamin B₁₂ is a direct clue, as it contains the root 'cobal' from cobalt.
Confirm this by mentally reviewing the composition of the other vitamins. Vitamins A, B₁, and B₆ are organic molecules without a central metal ion.
Select Vitamin B₁₂ based on this direct association between 'cobalt' and 'cobalamin'.

Concept Tested & Keywords

QCMVQUTikoGWLnDAOGU_26

E6 Biochemistry U Satyanarayana— Part 1 (pp 26-420 of 840) p. 140-142

E6 Ghai Essential Pediatrics(pp 26-904 of 913) p. 110-112

Practise the full UPPSC 2017

Attempt every question from this paper in a timed mock, then review the full solution for each one.