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Question
Does the sex of the child depend on the father or it is just a matter of chance? Discuss.
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Solution
The sex of the child depends on the father. The egg contains only one X chromosome, but half of the sperm contain an X chromosome whereas the other half contains a Y chromosome. It is simply a matter of chance as to which category of sperm fuses with the ovum and this determines whether the child will be male or female.
If the egg fuses with X-bearing sperm, the resulting combination is XX and the resulting child is female. If the egg fuses with Y-bearing sperm, the resulting combination is XY and the resulting child is male.
RELATED QUESTIONS
A new born child has an XY pair of chromosmes. Will it be a baby boy or a baby girl?
Fill in the following blank with suitable word :
Genes always work in ................ .
The person A has only B chromosomes in all its gametes. On the other hand, another person C has chromosome D in half of gametes and chromosome E in the other half of gametes. When chromosomes B and D combine during fertilisation, a female zygote results. On the other hand, combination of B and E chromosomes produces a male zygote.
(a) What are chromosomes (i) B (ii) D, and (iii) E?
(b) Out of B, D and E, which two chromosomes are of the same type?
(c) Which chromosome is smaller in size?
(d) What is the general name of chromosomes such as B and E?
(e) Out of the two persons A and C, which one is (i) male, and (ii) female?
Write the functional activity of the following structure:
Heterosomes
Brief about female heterogamety.
Read the following statements and select the correct option.
i. If sperm containing Y chromosome fertilizes the ovum, then diploid zygote is formed that grows into a male child.
ii. If sperm containing X chromosome fertilizes ovum, then diploid zygote is formed, that grows into a female child.
Sex is determined in human beings ______.
ZZ/ZW type of sex determination is seen in ______.
Select the statements that describe characteristics of genes
- genes are specific sequence of bases in a DNA molecule
- a gene does not code for proteins
- in individuals of a given species, a specific gene is located on a particular chromosome
- each chromosome has only one gene
What is sex determination? Explain the mechanism of sex determination in the case of birds.
