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Question : 38
Total: 39
All human chromosomes are 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 anX
(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
Solution:
(a) Gametes are haploid cells. Egg and sperm cells have just 23 chromosomes each. That's half as many chromosomes as regular cells. The fusion of two haploid cells results in the formation of a diploid cell. Therefore, zygote is a diploid cell with 46 chromosomes.
(b) Some animals (reptiles) rely entirely on environmental cues for sex determination. In some reptiles, the temperature at which fertilized eggs are kept determines whether the developing animal in the egg is male or female. Ex-lizard. In some animals like the snail, an individual can change sex under different stress and environmental conditions.
(c) The sex of a newborn child is purely and completely a matter of chance and none of the parent i.e. mother and father may be considered answerable for it. The statement in question is justified and can be proved by the process of fertilization:
(c) Human females are homomorphic. They have two sex chromosomes that are identical. One X-chromosome enters each gamete during meiosis at the time of gamete formation. So, all gametes have an X-chromosome.
(b) Some animals (reptiles) rely entirely on environmental cues for sex determination. In some reptiles, the temperature at which fertilized eggs are kept determines whether the developing animal in the egg is male or female. Ex-lizard. In some animals like the snail, an individual can change sex under different stress and environmental conditions.
(c) The sex of a newborn child is purely and completely a matter of chance and none of the parent i.e. mother and father may be considered answerable for it. The statement in question is justified and can be proved by the process of fertilization:
OR
(c) Human females are homomorphic. They have two sex chromosomes that are identical. One X-chromosome enters each gamete during meiosis at the time of gamete formation. So, all gametes have an X-chromosome.
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