Question

A zygote which has an X-chromosome inherited from the father will develop into a

• A. boy
• B. girl
• C. X- chromosome does not determine the sex of a child
• D. either boy or girl

Answer 1

The correct option is B

girl

The correct option is B:

Explanation of correct option-

1. Human cells have 23 pairs of chromosomes in which 22 pairs are autosomes and one pair is sex chromosome.
2. Sex chromosomes of women have two X chromosomes and men have one X and one Y chromosome.
3. Therefore, a female produces gametes which are all of the same kind and only contribute one chromosome to the zygote.
4. The other chromosome comes from the male and it can be either the X or Y chromosome.
5. In mammals, the Y chromosome determines the sex of the offspring as it contains the SRY gene which triggers male development.

Case 1- If an X chromosome arrives from the male then the zygote will have XX chromosomes on fusion with the X chromosome of the female and the resulting offspring will be a female (daughter).
Case 2- If a Y chromosome arrives from the male then the zygote will have XY chromosomes on fusion with the X chromosome of the female and the resulting offspring will be a male (son).

Final answer: A zygote which has an X-chromosome inherited from the father will develop into a girl.