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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.
संबंधित प्रश्न
Explain sex determination in human beings.
Write the types of sex-determination mechanisms the following crosses show. Give an example of each type.
(i) Female XX with Male XO
(ii) Female ZW with Male ZZ
How is the sex of the child determined in human beings?
Name the species used in sericulture. Name the stages in the life cycle of a silk moth in cyclic form.
In a human, how many chromosmes are present in a brain cell?
Does genetic combination of mother play a significant role in determining the sex of a new born baby?
The two versions of a trait (character) which are brought in by the male and female gametes are situated on :
(a) copies of the same chromosome
(b) sex chromosomes
(c) two different chromosomes
(d) any chromosomes
A couple with a newborn baby is troubled that the child does not resemble either of them. Suspecting that a mixup occurred at the hospital, they check the blood type of the infant. It is type O. Because the father is type A and the mother type B, they conclude that a mixup has definitely occurred. Are they correct? Give reason for your answer.
Name any two genetic in humans.
Why did T. H. Morgan select Drosophila melanogaster to study sex linked genes for his lab experiments ?
Define the following:
Sex chromosomes
Choose the correct answer:
Males have more chances of suffering from sex-linked disease because of ___________
Choose the correct answer:
A man can transfer his sex-linked gene to his ______________
What is male heterogamety?
Identify the female heterogamety from the chromosomal complements given below.
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 ______.
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
Which of the following decides the sex of the child?
A trait in an organism is influenced by
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
Fill the blank circles in figure and identify the sex of child A and B.
The chromosomal constitution of a human female can be written as ______
In humans, males are heterogametic and females are homogametic. Explain. Are there any examples where males are homogametic and females heterogametic?
Which of the following group shows ZW-ZZ type of sex determination?
