Question

Pairs of homologous chromosomes present in humans is
(a) 46
(b) 44
(c) 23
(d) 22

Answer 1

Hint: A similarity in internal or chromosomal structures is known as homologous. It also indicates organs that have similar structures or evolutionary origins and don't have to have the same function to be homologous.

Complete answer:
The molecule of a DNA (deoxyribonucleic acid) which contains a part or all of the genetic material of an organism is called Chromosome. Multi-cellular organisms have special cells called gametes for reproduction which contain only half the number of chromosomes. So when gametes from two different parents combine during reproduction, it results in a new individual, which contains DNA (the genetic material passed from parents) and a re-established number of chromosomes. Humans usually have 23 pairs of chromosomes (or we can say a total of 46 chromosomes). The autosomes (1-22 chromosome pairs) are the same in males and females. Chromosome pair 23 is dissimilar for males and females i.e. females have two X chromosomes, whereas males have an X chromosome and a much smaller Y chromosome. This 23rd pair determines the sex of the human. If the Y-chromosome in the zygote is inherited from the father then it is a male and if the X-chromosome is inherited from the father, the zygote will develop into a girl.
So, the correct answer is ‘22’.

Note: X chromosome contains a large amount of euchromatin (a lightly packed form of chromatin) and a small amount of heterochromatin (condensed chromatin structure) whereas; Y chromosome contains a small amount of euchromatin and a large amount of heterochromatin. Genes present in the X chromosome shows criss cross inheritance and genes present in the Y chromosome shows linear inheritance.