The process of copying the DNA sequence of a gene into messenger RNA (mRNA) is called?

RUHS, Jaipur, M.Sc Nursing Entrance Exam-2016

Pathology & Genetics

Easy

Appeared in: RUHS, Jaipur, M.Sc Nursing Entrance Exam-2016

Explanation

Transcription is the process where a specific segment of DNA (a gene) is used as a template to synthesize a complementary messenger RNA (mRNA) molecule.
It is the first of two main stages of gene expression, the second being translation.
This synthesis is catalyzed by the enzyme RNA polymerase, which reads the DNA template and assembles the new RNA strand.
The resulting mRNA carries the genetic code from the DNA in the nucleus to the ribosomes in the cytoplasm, where it will direct protein synthesis.

Option A: This is a general, non-scientific term in this context. It does not describe a specific process in molecular biology.
Option C: In genetics, translocation is a type of chromosomal abnormality where a piece of one chromosome breaks off and attaches to another. In protein synthesis, it refers to the movement of the ribosome along the mRNA strand. Neither definition matches the question.
Option D: Translation is the second major step in gene expression. It uses the mRNA molecule (produced during transcription) as a template to synthesize a chain of amino acids, forming a protein.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Central Dogma of Molecular Biology: Transcription as background academic context rather than a clinical decision trigger.
Understanding transcription is crucial for comprehending many genetic diseases. A mutation in a gene's DNA sequence can lead to the production of a faulty mRNA during transcription, resulting in a non-functional or harmful protein.
Many antibiotics, such as Rifampicin (used to treat tuberculosis), function by inhibiting the bacterial RNA polymerase enzyme. This blocks transcription in the bacteria, preventing them from producing essential proteins and ultimately killing them.
What if? If a mutation occurred in a gene's promoter region (the 'start' signal for transcription), RNA polymerase might not be able to bind to the DNA. This would prevent or significantly reduce transcription of the gene, leading to a deficiency of the corresponding protein, which could cause a genetic disorder.

How to Approach the Question

Identify the core process described in the question: the creation of an mRNA molecule from a DNA template.
Recall the 'Central Dogma of Molecular Biology,' which outlines the flow of genetic information: DNA → RNA → Protein.
Recognize that the first step, DNA → RNA, is called 'Transcription.'
Recognize that the second step, RNA → Protein, is called 'Translation.'
Compare these definitions to the options provided. 'Transcription' is the only term that correctly describes the process of copying DNA into mRNA.
Eliminate the other options: 'Translation' is the subsequent step, and 'Transference' and 'Translocation' have different meanings in a biological context.

Concept Tested & Keywords

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