How many chromosomes are present in the human body?

Appeared in: SGPGI Nursing Officer-2022

Explanation

Human somatic (non-sex) cells are diploid, containing a total of 46 chromosomes.
These chromosomes are organized into 23 pairs: 22 pairs of autosomes (non-sex chromosomes) and one pair of sex chromosomes (XX for females, XY for males).
This number is restored during fertilization when a sperm and egg, each containing 23 chromosomes (haploid), unite.
The discovery that the normal human karyotype contains 46 chromosomes was a major breakthrough in genetics.

Option A: 42 is not the standard chromosome number for any human cell type.
Option B: 44 represents only the autosomes (22 pairs) in a human cell. It omits the two sex chromosomes (XX or XY) that are also present.
Option D: 48 is the chromosome number for other primates like gorillas, chimpanzees, and potatoes, but not for humans.

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.
Understanding the correct chromosome number is fundamental for genetic counseling and diagnosing chromosomal abnormalities.
Aneuploidy, an incorrect number of chromosomes (e.g., 45 or 47), leads to genetic disorders such as Down syndrome (Trisomy 21), Turner syndrome (45,X), and Klinefelter syndrome (47,XXY).
Nurses play a key role in educating and supporting families affected by chromosomal disorders, explaining test results like karyotypes, and managing care.

How to Approach the Question

This is a factual recall question asking for a specific number from basic human biology.
Identify the keywords in the question: 'how many', 'chromosomes', and 'human body'.
Recall the standard diploid number for human somatic cells, which is a fundamental concept in genetics.
Evaluate the given options. 46 is the well-established number for humans.
Consider why the other options are incorrect: 44 excludes the sex chromosomes, and 48 is characteristic of other species (like great apes).
Select the option that matches the correct biological fact for humans.

Concept Tested & Keywords

Qw16UuBfn5k3TIfJwd0z3j

E6 Parks TextBook of Preventive & Social Medicine part 2 — Subpart B (pp 233-449 of 464) p. 138-140

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

Practise the full SGPGI Nursing Officer-2022

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