Question

How is the sex of an offspring determined in humans?
a. Sex chromosomes of mother
b. Size of ovum
c. Size of sperm
d. Sex chromosome of father.

Answer 1

Hint: The sex chromosomes are: XX for female, or XY for the males. They participate in sex determination. Sex is the hereditary difference between two individuals of the same species. Males are known as heterogametic because they possess the Y chromosome.

Complete answer:
In a human being, depending upon the type of male gamete (on the basis of which sex chromosome they are having i.e., X or Y) fertilizes with the female gamete the sex of an offspring is determined. In each of the mother and father, there are pairs of the chromosomes. Out of the pairs, pairs are said to be autosomes and one pair is called sex chromosomes. At the time of fertilization, to form the zygote, the sperm fertilizes the egg cell. If the sperm carrying X chromosome fertilizes an ovum carrying an X chromosome, then the offspring born will be a girl. Fertilizes an ovum carrying X chromosome when the sperm carries Y chromosomes, the offspring then born will be a baby.

Hence, the sex chromosome of father i.e. option‘d’ is the correct answer.

Note:
There will be two types of sperm cells produced in equal numbers at the time of spermatogenesis, one containing an X chromosome and the other containing a Y chromosome. At the centre, two short arms (P arms), two longer arms (q arms) and a centromere are present in each chromosome.