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प्रश्न
Explain the mechanism of sex determination in birds.
उत्तर
- In birds, the chromosomal mechanism of sex determination is ZW-ZZ type.
- In this type females are heterogametic and produce two types of eggs; 50% of eggs carry Z-chromosome, while 50% of eggs carry W- chromosome.
- Males are homogametic and produce one type of sperms. Each sperm carries a Z chromosome.
- Thus, the sex of an individual depends on the kind of egg (ova) fertilized by the sperm.
संबंधित प्रश्न
Differentiate between male and female heterogamety
Which of the two, sperm or ovum, decides the sex of the child?
In a human, how many chromosmes are present in a brain cell?
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.
Does the sex of the child depend on the father or it is just a matter of chance? Discuss.
Distinguish between heterogametic and homogametic sex determination systems.
How many ovum are formed when a diploid cell undergoes meiosis, during oogenesis?
Which of the following determines the sex of a child?
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?
The sex chromosome in a human ovum is ______.
