what is zygote??And how is it produced?
Answers
Answer:
Zygote, fertilized egg cell that results from the union of a female gamete (egg, or ovum) with a male gamete (sperm). In the embryonic development of humans and other animals, the zygote stage is brief and is followed by cleavage, when the single cell becomes subdivided into smaller cells.
Answer:
A zygote is the first diploid cell that is formed by the fusion of male and female gametes resulting in the formation of an embryo.
The zygote stage development occurs in the first week of fertilization. The genome of the zygote is the combination of DNA in each gamete and contains all the genetic information required to form an individual.
Formation Of Zygote
The earliest form of zygote shows pronuclei where haploid germ cells from the male and female fuse with each other, breaking down the nuclear membrane, but they do not merge. Hence, they are single nucleic cells at this point.
The first stage of mitotic division occurs where genetic information is exchanged and chromosomes are paired, resulting in DNA replication at the spindle apparatus of the equator brought about by – the spermatozoa (centrioles) and the oocyte contributing the mitochondria. Thus, the first new cell – the zygote, with a chromosomal makeup of 2n4c is formed due to the alignment of chromosomes from both the sets at the spindle.
Development of Zygote
The development of zygote takes place in several stages mentioned below:
The zygote rapidly divides after the first 12-24 hours of formation
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The cell mass forms a hollow ball during blastulation
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Cells start differentiating and form cavities
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The three germ layers form during gastrulation
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Formation of primitive streak followed by notochord formation
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Tubes are formed making a neurula
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The notochord forms the neural plate
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The neural plate folds to form a neural tube and neural crest
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The mesoderm is divided into axial, paraxial, intermediate and lateral plate mesoderm, which gives rise to different organs.