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प्रश्न
Differentiate between ‘ZZ’ and ‘XY’ type of sex-determination mechanisms.
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उत्तर
| ZZ Sex-Determination Mechanism | XY Sex-Determination Mechanism |
| In this type of chromosomal sex determination mechanism, the females are heterogametic, that is, they produce two types of gametes, while the males are homogametic. | In this type of chromosomal sex determination mechanism, the males are heterogametic, that is, they produce two types of gametes, while the females are homogametic. |
| Here, the females produce two types of eggs (A + Z) and (A + W), while the males produce only one type of sperm (A + Z). | Here, the males have an X chromosome and its counterpart Y chromosome, which is distinctly smaller. Hence, the males are XY. However, females have a pair of X chromosomes; therefore, they are XX. |
| Organisms that have the ZZ type of sex-determination mechanism are birds, fishes, some reptiles, etc. | Organisms that have the XY type of sex-determination mechanism are humans and Drosophila. |
संबंधित प्रश्न
There are ................ pairs of chromosomes in the human being.
Which of the following combinations of sex chromosomes produce a male child : XX or XY?
In a human, how many chromosmes are present in an egg which has just been produced by the ovary?
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.
A family consists of two parents and their five children and the pedigree chart below shows the inheritance of the trait colour blindness in them.
Who is colour blind in the parents – the Father or the Mother?
Define the following:
Sex-linked characters
Complete the following sentence with appropriate word:
___________ chromosomes do not take part in sex determination.
What is parthenogenesis?
What is Lyonisation?
Explain the mode of sex determination in honeybees.
How many ovum are formed when a diploid cell undergoes meiosis, during oogenesis?
Read the following statements and select the correct option.
i. If sperm containing Y chromosome fertilizes the ovum, then diploid zygote is formed that grows into a male child.
ii. If sperm containing X chromosome fertilizes ovum, then diploid zygote is formed, that grows into a female child.
Diploid larvae which get royal jelly as food develops into ____________ and other develops into workers (sterile females).
If a normal cell of the human body contains 46 pairs of chromosomes then the numbers of chromosomes in a sex cell of a human being is most likely to be ______
Which of the following statements is not true with respect to variation?
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
Does a male child inherit X chromosome from his father? Justify.
