Advertisements
Advertisements
प्रश्न
How is sex determined in human beings?
Advertisements
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.
APPEARS IN
संबंधित प्रश्न
If X chromosome is inherited from mother and Y from father, the offspring will be male.
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
Name the species used in sericulture. Name the stages in the life cycle of a silk moth in cyclic form.
Which of the following is an example of ZW – ZZ type of mechanism of sex determination?
Explain the mechanism of 'sex determination' in birds. How does it differ from that of human beings?
What are the chromosomes XY and XX known as?
A new born child has an XY pair of chromosmes. Will it be a baby boy or a baby girl?
Which of the following combinations of sex chromosomes produce a male child : XX or XY?
Fill in the following blank with suitable word :
Genes always work in ................ .
Fill in the following blank with suitable word :
The...............chromosomes for a ............are XX whereas that for a ..............are XY.
The human animal which has an XY pair of chromosomes is called :
(a) male
(b) hybrid
(c) female
(d) doomed
The sex of a child is determined by which of the following?
- E is the gene for brown eye colour and e is the gene for blue eye colour. Which gene is (i) recessive, and (ii) dominant?
- Both father and mother have the genes Ee in their cells. What colour are their eyes?
- Which combination of genes in the zygote will produce children with blue eyes?
- Which combinations of genes in the zygote will produce children with brown eyes?
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 two animals which have nineteen pairs of chromosomes.
Define the following:
Sex chromosomes
Choose the correct answer:
Males have more chances of suffering from sex-linked disease because of ___________
Complete the following sentence with appropriate word:
___________ chromosomes do not take part in sex determination.
XO type of sex determination and XY type of sex determination are examples of ____________.
Which of the following is incorrect regarding ZW-ZZ type of sex determination?
What is Lyonisation?
There are five daughters and no son in a family. It is because
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 |
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.
Sex is determined in human beings ______.
Which of the following is incorrect regarding ZW - ZZ type of sex determination?
Haplodiploidy is found in ______.
Female heterogamy is shown by
Name the two types of gametes produced by men.
Which of the following group shows ZW-ZZ type of sex determination?
Which pair of sex chromosome will determine a male?
If a male grasshopper with XO genotype produces sperm, what proportion of his sperm will carry the X chromosome?
In a bird population using the ZW–ZZ sex determination system, if a ZZ male mates with a ZW female, what proportion of offspring would be expected to be female?
