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Question
How is sex determined in human beings?
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Solution
The XX-XY chromosomal pattern determines sex in humans. Humans possess 22 pairs of autosomes and one pair of sex chromosomes. The female has two homomorphic sex chromosomes called XX. The males have two heteromorphic sex chromosomes, XY. Female oocytes have equivalent chromosomal types (22 + X). As a result, girls are homogametic. Human males produce two types of male gametes or sperm: gynosperms (22 + X) and androsperms (22 + Y). Human males are hence heterogametic. The gender of the offspring is determined at fertilisation. Fertilisation of the egg (22 + X) with a gynosperm (22 + X) results in a female child (44 + XX), whereas fertilisation with an androsperm (22 + Y) results in a male child (44 + XY). Because the two types of sperm are produced in equal quantities, there is an equal possibility of having a male or female child in a given pairing. The Y-chromosome, which defines an individual’s male sex, is also known as the androsome.
RELATED QUESTIONS
Answer the following questions related to sex determination in human beings:
i. What is sex chromosome?
ii. How many pairs of chromosomes are present in human beings?
iii. How is the sex of the human offspring determined?
iv. Draw a diagram depicting sex determination in man.
"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.
How is the sex of the child determined in human beings?
There are two sets of chromosomes in the zygote.
What are the chromosomes XY and XX known as?
Which of the two, sperm or ovum, decides the sex of the child?
A new born child has an XY pair of chromosmes. Will it be a baby boy or a baby girl?
In a human, how many chromosmes are present in a sperm in the testes?
In human males all the chromosomes are paired perfectly except one. This/these unpaired chromosomes is/are :
(i) large chromosome
(ii) small chromosome
(iii) Y chromosome
(iv) X chromosome
Define the following:
Autosomes
Define the following:
Sex chromosomes
Complete the following sentence with appropriate word:
___________ chromosomes do not take part in sex determination.
Short Answer Question.
“Father is responsible for determination of sex of child and not the mother”. Justify.
Differentiate Intersexes from Supersexes.
Diploid larvae which get royal jelly as food develops into ____________ and other develops into workers (sterile females).
ZZ/ZW type of sex determination is seen in ______.
Grasshopper is an example of XO type of sex determination in which the males have ______.
A man with blood group A marries a woman having blood group O. What will be the blood group of the child?
Which of the following is an example of genetic variation?
Select the incorrect statement
Fill the blank circles in figure and identify the sex of child A and B.
Sex in honey bee is determined by ______.
Also describe as to, who determines the sex of an unborn child? Mention whether temperature has a role in sex determination.
What is the probability of a girl or a boy being born into a family? Justify your answer.
What is sex determination? Explain the mechanism of sex determination in the case of birds.
A zygote which has Y chromosome inherited from the father will develop into a ______.
