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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.
Explain the mechanism of 'sex determination' in birds. How does it differ from that of human beings?
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.
With the help of a chart, explain the method of sex determination in honeybees.
In which livings, female decides the sex? Give two examples.
XO type of sex determination and XY type of sex determination are examples of ____________.
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 |
Chromosomal constitution of normal human females can be written as ______.
Grasshopper is an example of XO type of sex determination in which the males have ______.
A zygote which has an X-chromosome inherited from the father will develop into a ______.
A woman has only daughters. Analyse the situation genetically and provide a suitable explanation.
Structures present in a cell which is responsible for determination of the sex of a baby is ______.
Female heterogamy is shown by
How many types of gametes are produced by a human female?
All human chromosomes ate not paired. Most human chromosomes have a maternal and a paternal copy, and we have 22 such pairs. But one pair called the sex chromosomes, is odd in not always being a perfect pair. Women have a perfect pair of sex chromosomes. But men have a mismatched pair in which one is normal sized while the other is a short one.
(a) In humans, how many chromosomes are present in a Zygote and in each gamete?
(b) A few reptiles rely entirely on environmental cues for sex determination. Comment.
(c) "The sex of a child is a matter of chance and none of the parents are considered to be responsible for it." Justify it through flow chart only.
OR
(c) Why do all the gametes formed in human females have an X chromosome?
What is the probability of a girl or a boy being born into a family? Justify your answer.
Given below are two statements:
Statement - I: The male Drosophila has a pair of homomorphic sex chromosomes.
Statement - II: The male human being has a pair of heteromorphic sex chromosomes.
In the light of above statements, Choose the most appropriate answer from the options given below:
