Question

Answer the following questions related to sex determination in human beings:
(i) What is a sex chromosome?
(ii) How many pairs of chromosomes are there in human beings?
(iii) How is the sex of the human offspring determined?
(iv) Draw a diagram depicting sex determination in man.

Answer 1

(i) Sex chromosome is the chromosome that determines the sex of a human being.

(ii) There is one pair of sex chromosomes present in a human being.

(iii) The offspring receives one chromosome from each of the parents. Here, they inherit one X chromosome essentially from the mother because she has two X chromosomes. On the other hand, the father has two different chromosomes, i.e. one X chromosome and one Y chromosome. Therefore, the sex of the offspring is determined by either of the chromosomes that they inherit from their father. If the genotype of the offspring is XX then the offspring will be a female and if is XY then it will be a male.

(iv) The given diagram illustrates sex determination in man.