Question

(a) How many pairs of autosomes and Paris of sex chromosomes are present in a human being?  

(b) Which chromosomes are present in Females? 

(c) Which chromosomes are present in Male? 

(d) How does sex determination take place in human beings? 

Answer 1

a. There are 22 pairs of autosomes and one pair of sex chromosomes present in human beings.

b. In females 22 pairs of autosomes and XX sex chromosomes are present.

c. In males 22 pairs of autosomes and XY pair of sex chromosomes.

d. In human males, two dissimilar chromosomes are present in 23^rd pair, the longer 'X' and the shorter 'Y'. In females, the 23^rd pair contains two similar 'X' chromosomes. All children inherit one 'X' chromosome from their mother. The other chromosome is inherited from the father. If the chromosome inherited from the father is 'X', then the offspring is a daughter and if it is 'Y', then the offspring is a son.

Thus, the sex of the child is determined by the male sex chromosome.