What is the number of chromosomes present in the gametes (egg and sperm) of human beings? & x20; - RRB Nsg. Superintendent-21 July 2019 (Shift-2nd)

RRB Nsg. Superintendent-21 July 2019 (Shift-2nd)

Pathology & Genetics

Easy

Appeared in: RRB Nsg. Superintendent-21 July 2019 (Shift-2nd)

Explanation

Human gametes (sperm and egg) are reproductive cells that contain a single set of chromosomes.
This is known as the haploid (n) number, which in humans is 23 chromosomes.
Gametes are produced by meiosis, a type of cell division that halves the chromosome number from the diploid (2n) state of somatic cells.
The fusion of a haploid sperm and a haploid egg during fertilization restores the diploid number (46 chromosomes) in the resulting zygote.

Option A: Gametes are the carriers of genetic material (DNA) organized into chromosomes. Without chromosomes, there would be no transfer of hereditary traits to the offspring.
Option C: This describes the number of autosomes (non-sex chromosomes) in a diploid somatic cell, not the total chromosome content of a haploid gamete. Gametes do not have chromosome pairs.
Option D: This describes a triploid (3n) state, which is a type of polyspermy or chromosomal abnormality in humans and is not the normal chromosome number for gametes.

Visual 1: Diagram - A flowchart illustrating the process of meiosis, showing a diploid parent cell (46 chromosomes) dividing twice to produce four haploid gametes (each with 23 chromosomes). This visually clarifies the chromosome reduction.
Visual 2: Infographic - A comparison chart contrasting a diploid somatic cell (showing 23 pairs of chromosomes) with a haploid gamete (showing 23 single chromosomes). This helps differentiate between the two cell types.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Chromosome number in human gametes (haploid vs. diploid) as background academic context rather than a clinical decision trigger.
Understanding the haploid nature of gametes is fundamental to genetics and reproductive health. It explains how genetic traits are passed from parents to children.
Errors in meiosis can lead to aneuploidy (an abnormal number of chromosomes) in the gametes. If such a gamete is involved in fertilization, it can result in genetic disorders like Down syndrome (Trisomy 21), Turner syndrome (Monosomy X), or Klinefelter syndrome (XXY).
This knowledge is crucial for genetic counseling, where couples are advised on the risks of inheriting or passing on genetic conditions.

How to Approach the Question

First, identify the key terms in the question: 'gametes' (egg and sperm) and 'number of chromosomes'.
Recall the basic principles of human genetics. Remember that human body cells (somatic cells) are diploid (2n) and reproductive cells (gametes) are haploid (n).
Define what 'diploid' and 'haploid' mean in terms of chromosome sets. Diploid means two sets, and haploid means one set.
Apply this knowledge to the options. A gamete has one set of chromosomes.
Evaluate the other options to confirm they are incorrect. 'No chromosomes' is impossible. '22 pairs' refers to autosomes in a diploid cell. 'Three sets' describes a triploid condition, which is an abnormality.

Concept Tested & Keywords

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