Question

A human cell containing 22 autosomes and a Y chromosome is probably a
A. Somatic cell of a male
B. Sperm cell
C. Somatic cell of a female
D. Unfertilized egg cell

Answer 1

There are two categories of chromosomes– autosomes and allosomes. All chromosomes are autosomes besides sex chromosomes. In the human genome on the basis of their sizes autosomes have been numbered. All sex chromosomes exist in pairs in the somatic cells whereas single in the gametic cells.

Complete answer:
Let us find the correct answer,
- Option A is given to somatic cells of male which is wrong because somatic cells of human male contain a single barr body. It has two X chromosomes and its genetic competition would be XXY.
- Option B is given a sperm cell which is correct because each cell of the nucleus contains 23 pairs of chromosomes in humans, a total of 46 chromosomes. Autosomes are the first 22 pairs of chromosomes. The chromosomes of the 23rd pair are called autosomes consisting of two X (XX) chromosomes which occur in most females, and an X chromosome and a Y chromosome in most males. The X chromosome is always present as the 23rd chromosome in the ovum, while either an X or a Y chromosome can be present in an individual sperm.
- Option C is the somatic cell of the female which is the wrong option because a female somatic cell does not produce a sperm or egg.

Hence the correct answer is option B.

Note: In genotypically human females barr bodies are found in. One barr body is found per somatic cell. This is a type of deactivated X chromosome which is seen as a small dark staining structure in the nucleus. Barr's body is found in male only in case of Klinefelter syndrome.