How many pairs of chromosomes are found in a cell of a human being?

Appeared in: NHM UP Staff Nurse - 2017

Explanation

Human somatic cells are diploid, meaning they contain two sets of chromosomes, one inherited from each parent.
The total number of chromosomes is 46, which are organized into 23 pairs.
These pairs consist of 22 pairs of autosomes (which determine non-sex-related traits) and one pair of sex chromosomes (XX in females, XY in males).

Option B: This is an incorrect number. The number of chromosome pairs in humans is a fixed biological constant.
Option C: This is an incorrect number. It does not represent the diploid or haploid number of chromosomes in human cells.
Option D: This is an incorrect number. The count of 23 pairs is a defining characteristic of the human species.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Human Chromosome Number as background academic context rather than a clinical decision trigger.
Knowledge of the normal chromosome count (23 pairs) is fundamental for identifying genetic disorders caused by aneuploidy, which is an abnormal number of chromosomes.
Conditions like Down syndrome (Trisomy 21), where there are three copies of chromosome 21 instead of the usual pair, are diagnosed through karyotyping.
What if? If a person had only one X chromosome and no Y chromosome (a total of 45 chromosomes), they would have Turner syndrome, a condition that affects development in females. This highlights the critical role of having a complete pair of sex chromosomes.

How to Approach the Question

Identify the key terms in the question: 'pairs of chromosomes' and 'human being'.
Recognize this as a factual recall question from basic biology and genetics.
Recall that human somatic (body) cells are diploid, meaning their chromosomes come in pairs.
Remember the total number of chromosomes in a human cell is 46.
To find the number of pairs, divide the total number by two: 46 chromosomes / 2 = 23 pairs.
Scan the options and select the one that matches your calculation.

Concept Tested & Keywords

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E6 Psychology Baron Misra 5e Part 1 p. 90-92

E6 Parks TextBook of Preventive & Social Medicine part 2 — Subpart B (pp 233-449 of 464) p. 137-139

E6 Pathology-Vandana Puri & Kavita Gaur Textbook of Pathology and Genetics p. 472-474

Practise the full NHM UP Staff Nurse - 2017

Attempt every question from this paper in a timed mock, then review the full solution for each one.