One of the following controls normal growth and proliferation of cells :

IGNOU PB Bsc Nsg.Entrance-2026

Pathology & Genetics

Easy

Appeared in: IGNOU PB Bsc Nsg.Entrance-2026

Explanation

Proto-oncogenes are normal cellular genes whose protein products are essential for promoting controlled cell proliferation and differentiation.
They function as the 'gas pedal' of the cell cycle, ensuring that cells divide when necessary for normal physiological processes like tissue repair and development.
The term 'proto' signifies their role as precursors; they are the normal, unmutated versions of genes that can become oncogenes.
Examples of proto-oncogenes include MYC, RAS, and genes for growth factors like PDGF, which are all involved in signaling pathways that stimulate cell division.

Option A: Oncogenes are mutated versions of proto-oncogenes. They do not control normal growth; instead, they cause abnormal, uncontrolled, and autonomous cell proliferation, which is a hallmark of cancer.
Option C: Antioncogenes, also known as tumor suppressor genes (e.g., p53, RB), have the opposite function. They inhibit or suppress cell growth and division, acting as the 'brakes' of the cell cycle.
Option D: Promoters are specific DNA sequences located near a gene. They act as a binding site for RNA polymerase to initiate transcription (the first step in gene expression). While they are crucial for gene regulation, they are not the genes themselves that code for proteins controlling cell growth.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Regulation of normal cell growth and proliferation by specific genes as background academic context rather than a clinical decision trigger.
Understanding the difference between these genes is fundamental to oncology nursing. Many targeted cancer therapies are designed to inhibit the protein products of specific oncogenes (e.g., HER2 inhibitors in breast cancer).
Nurses often educate patients and families about genetic testing for mutations in antioncogenes (like BRCA1/2), which can indicate a hereditary risk for developing certain cancers.
This knowledge helps in counseling patients on risk-reduction strategies, screening, and potential prophylactic treatments.

How to Approach the Question

First, identify the key phrase in the question stem: 'controls normal growth'. This qualifier is critical for distinguishing between the options.
Analyze the prefix of each term. 'Proto-' means 'first' or 'precursor,' suggesting a normal state. 'Onco-' relates to tumors or cancer. 'Anti-' means 'against.'
Based on the prefixes, 'Proto-oncogenes' are the most likely candidates for regulating 'normal' processes.
Eliminate 'Oncogenes' because they are associated with abnormal, cancerous growth.
Eliminate 'Antioncogenes' as their function is to suppress or inhibit growth, not promote it.
Differentiate between 'Proto-oncogenes' (the genes coding for growth-regulating proteins) and 'Promoters' (the DNA sequences that initiate gene expression). The question asks what 'controls' growth, which refers to the functional gene, not just its switch.

Concept Tested & Keywords

Concept Tested: Regulation of normal cell growth and proliferation by specific genes.
Stem keywords: controls, normal growth, proliferation, cells
Lead-in keywords: One of the following
Negative lead-in flag: false

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