Question

6. Answer the following questions on
a) Define sex chromosomes.
b) Explain how the number of sex chromosomes in a gamete is different
from a normal cell.
c) With the help of a schematic diagram, show how a female and a male
zygote is formed during fertilisation.​

Answer 1

Answer:

a) The chromosomes which help in the identification of a baby's sex are called sex chromosomes. they are X and Y.

b)

Answer 2

Answer:

In the human being, the chromosomal mechanism of sex determination is of XX-XY type. In human the nucleus of each cell contains 46 chromosomes or 23 pairs of chromosomes of body characters) and 1 pair is of sex chromosomes (responsible for determination of sex).

1. In the female, two homomorphic sex chromosomes are XX.

2. In the male, two heteromorphic sex chromosomes are XY.

3. The genotypes of female and male is

Female : 46 Chromosomes = 44 Autosomes + XX sex chromosomes

Male : 46 Chromosomes = 44 Autosomes + XY sex chromosomes

solution