The transfer of genetic information from one generation to the other is accomplished by

RRB Staff Nurse Jaipur-6th June 2018

Pathology & Genetics

Easy

Appeared in: RRB Staff Nurse Jaipur-6th June 2018

Explanation

DNA (Deoxyribonucleic Acid) is the molecule responsible for storing and transferring genetic information from one generation to the next.
This process of passing genetic traits from parents to offspring is the basis of heredity.
While RNA molecules are essential for expressing genetic information (protein synthesis), only DNA serves as the permanent, heritable blueprint.

Option B: mRNA (messenger RNA) is a temporary copy of a gene's instructions. Its role is to carry the genetic code from the DNA to the cytoplasm for protein synthesis, a process called transcription. It does not transfer information between generations.
Option C: tRNA (transfer RNA) acts as an adapter molecule during protein synthesis. It transports specific amino acids to the ribosome to be added to the growing protein chain, a process called translation. It does not carry the primary genetic blueprint.
Option D: rRNA (ribosomal RNA) is a structural and catalytic component of ribosomes, the cellular machinery where proteins are assembled. It does not carry genetic information itself but is part of the structure that reads the mRNA.

Visual 1: Diagram: The Central Dogma of Molecular Biology. This visual shows the flow of genetic information from DNA (replication, storage) to RNA (transcription) and then to Protein (translation), clearly distinguishing the roles of each molecule.
Visual 2: Illustration: Comparison of DNA and RNA structures. This would show the DNA double helix, representing stability and long-term storage, contrasted with the single-stranded nature of mRNA, highlighting its role as a temporary message.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Heredity and the roles of nucleic acids (DNA and RNA) as background academic context rather than a clinical decision trigger.
Understanding that DNA is the molecule of heredity is fundamental to clinical genetics, including the diagnosis and counseling for genetic disorders like cystic fibrosis, sickle cell anemia, and Huntington's disease.
The function of mRNA is the basis for modern mRNA vaccines (e.g., for COVID-19). These vaccines provide cells with mRNA instructions to build a harmless piece of a virus, triggering an immune response without altering the patient's DNA.
What if the question asked, 'What process copies genetic information from DNA to RNA?' The answer would be 'Transcription,' highlighting the first step in gene expression rather than inheritance.

How to Approach the Question

Identify the key phrase in the question: 'transfer of genetic information from one generation to the other'. This is the definition of heredity.
Analyze the function of each option in the context of heredity versus gene expression.
Recall that DNA is the stable, double-stranded molecule that serves as the long-term storage of genetic information and is passed down through generations.
Recognize that mRNA, tRNA, and rRNA are primarily involved in the process of using the information within DNA to synthesize proteins inside a cell (gene expression), not in passing the information to the next generation.
Conclude that DNA is the only molecule listed whose primary role matches the process of heredity described in the question.

Concept Tested & Keywords

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