Vitamin B12 is essential for synthesis of-

RUHS, Jaipur, PB B.Sc Nursing Entrance-2024

Applied Nutrition & Dietetics

Easy

Appeared in: RUHS, Jaipur, PB B.Sc Nursing Entrance-2024

Explanation

Vitamin B12 is essential for DNA synthesis.
It acts as a cofactor for the enzyme methionine synthase, which is critical for folate metabolism.
This reaction regenerates tetrahydrofolate (THF), a molecule required for the synthesis of purines and pyrimidines, the building blocks of DNA.
A deficiency of Vitamin B12 'traps' folate in an unusable form, impairing DNA synthesis and leading to megaloblastic anemia.
This effect is most pronounced in rapidly dividing cells, such as hematopoietic precursors in the bone marrow.

Option B: Enzymes are proteins. Vitamin B12 is a coenzyme, which is a non-protein helper molecule for certain enzymes, but it is not a building block for the synthesis of the enzyme proteins themselves.
Option C: Immunoglobulins are proteins (antibodies) synthesized by B-lymphocytes (plasma cells). Their synthesis is part of general protein production and does not have a specific, direct dependency on Vitamin B12.
Option D: Hormones are a diverse group of signaling molecules, including steroids, peptides, and amino acid derivatives. Their synthesis pathways are highly specific to the hormone and gland, and do not generally rely on Vitamin B12 as an essential cofactor.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain The role of Vitamin B12 in cellular metabolism as background academic context rather than a clinical decision trigger.
Understanding the role of Vitamin B12 is critical for diagnosing and managing megaloblastic anemia, which is characterized by large, immature red blood cells.
Nurses must be aware of the neurological manifestations of B12 deficiency, such as peripheral neuropathy and subacute combined degeneration of the spinal cord, which can be irreversible if not treated promptly.
Patient populations at risk for B12 deficiency include strict vegans, older adults, individuals with pernicious anemia (lack of intrinsic factor), and those who have had gastric or ileal resection.

How to Approach the Question

This is a factual recall question that tests your knowledge of micronutrients.
First, identify the key subject: 'Vitamin B12'.
Recall the primary biochemical functions of Vitamin B12. The two most important are its role in DNA synthesis (via folate metabolism) and myelin synthesis.
Evaluate each option based on this knowledge.
Option A (DNA) directly matches one of the primary functions.
Options B, C, and D (Enzyme, Immunoglobulins, Hormones) are general categories of biological molecules whose synthesis is not directly and universally dependent on Vitamin B12.

Concept Tested & Keywords

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