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प्रश्न
How is sex determined in human beings?
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उत्तर
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.
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संबंधित प्रश्न
Differentiate between male and female heterogamety.
Explain the mechanism of sex determination in birds.
Differentiate between ‘ZZ’ and ‘XY’ type of sex-determination mechanisms.
"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.
If a normal human cell has 46 chromosomes, how many chromosomes will be there in a human sperm cell?
In a human, how many chromosmes are present in a sperm in the testes?
The exchange of genetic material takes place in :
(a) vegetative reproduction
(b) asexual reproduction
(c) sexual reproduction
(d) budding
A zygote which has inherited an X chromosome from the father will develop into :
(a) baby boy
(b) baby girl
(c) adult
(d) either boy or girl
Name two animals which have nineteen pairs of chromosomes.
Choose the correct answer from the four options given below :
In a human male, a sperm will contain :
Choose the correct answer:
A man can transfer his sex-linked gene to his ______________
Short Answer Question.
“Father is responsible for determination of sex of child and not the mother”. Justify.
Explain the haplo-diploid method of sex determination in the honey bee.
What is haplodiploidy?
What is Lyonisation?
Brief about female heterogamety.
From the following which option correctly represents the normal genetic constitution of a ovum?
Match the items of Column I with Column II:
| Column I | Column II | ||
| i. | XX-XO method of Sex Determination | a. | Turner syndrome |
| ii. | XX-XY method of Sex Determination | b. | Female heterog ametic |
| iii. | karyotype-45 | c. | Grasshopper |
| iv. | ZW-ZZ method of Sex Determination | d. | Female homogametic |
Which of the following organisms has haploid number of chromosomes?
The ‘X’ body of Henking was observed in ______.
ZZ/ZW type of sex determination is seen in ______.
Number of autosomes present in liver cells of a human female is ______.
Haplodiploidy is found in ______.
Which of the following combination of chromosome numbers represents the correct sex determination pattern in honey bees?
In human males all the chromosomes are paired perfectly except one. This/these unpaired chromosomes is/are ______.
- large chromosome
- small chromosome
- Y-chromosome
- X-chromosome
The number of pairs of sex chromosomes in the zygote of a human being is ______
A man with blood group A marries a woman having blood group O. What will be the blood group of the child?
Human offspring’s sex is determined ______
The maleness of a child is determined by
The two versions of a trait (character) which are brought in by the male and female gametes are situated on
Sex of an individual is determined by different factors in various species. Some animals rely entirely on the environmental ones, while in some other animals the individuals can change their sex during their life time indicating that sex of some species is not genetically determined. However in human beings, the sex of an individual is largely determined genetically.
- In what way are the sex chromosomes 'X' and 'Y' different in size? Name the mismatched pair of sex chromosome in humans.
- Write the number of pair/pairs of sex chromosomes present in human beings. In which one of the parent (male/female) perfect pair/pairs of sex chromosome are present?
- Citing two examples, justify the statement "Sex of an individual is not always determined genetically".
OR
Draw a flow chart to show that sex is determined genetically in human beings.
Which of the following group shows ZW-ZZ type of sex determination?
Which pair of sex chromosome will determine a male?
How is the sex of a newborn individual determined in different species of animals? Give three examples to support your answer.
A zygote which has Y chromosome inherited from the father will develop into a ______.
Twins are born to a family that lives next door to you. The twins are a boy and a girl. Which of the following must be true?
In the haplodiploidy system observed in honeybees, unfertilized eggs develop into which type of individual?
