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Question
Answer the following question:
How is sex determined in human beings? Explain with the help of a diagram.
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Solution
- In human beings, the gametes from the male parent decide the sex of the baby.
- In human beings, there are 22 pairs of autosomes and 1 pair of sex chromosomes.
- In human male gametes, two dissimilar sex chromosomes XY are present whereas in females two similar sex chromosomes XX are present.
- All children inherit 'X' chromosomes from their mother and 'X or 'Y' from their father.
- If it is X chromosome from father, then the offspring will be a daughter, and if 'Y' chromosomes, then it will be a son.
- Hence, the gametes from the male parent decide the sex of the baby.
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RELATED QUESTIONS
"The sex of a newborn child is a matter of chance and none of the parents may be considered responsible for it". Draw a flow chart showing determination of sex of a newborn to justify this statement.
The exchange of genetic material takes place in :
(a) vegetative reproduction
(b) asexual reproduction
(c) sexual reproduction
(d) budding
The sex of a child is determined by which of the following?
(a) the length of the mother's pregnancy
(b) the length of time between ovulation and copulation
(c) the presence of and X chromosome in an ovum
(d) the presence of a Y chromosome in a sperm
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?
Define the following:
Autosomes
Give Reason:
Why X-linked recessive diseases are more common among males than females.
Diploid larvae which get royal jelly as food develops into ____________ and other develops into workers (sterile females).
Identify the organism in which ZZ-ZW type of sex determination is observed.
Which of the following decides the sex of the child?
How is the sex of a newborn individual determined in different species of animals? Give three examples to support your answer.
