Is the chromosome number of the zygote, embryonal cells and adult of a particular organism always constant? How is the constancy maintained in these three stages?
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Solution
Yes, the chromosome number of a particular organism's zygote, embryonal cell, and adult is always constant.
Zygote, embryonal cell, and adult are always constant:
Meiosis is the process by which cells divide during gametogenesis.
As a result, the number of chromosomes in gametes is cut in half.
When fertilization occurs, the number of chromosomes equals that of somatic cells.
Mitosis then occurs during the remaining stages of life. As a result, the chromosomal number remains constant throughout all three stages.
Meiosis:
Meiosis is the process by which cells divide in sexually reproducing organisms.
The genetic material from the paternal and maternal copies of each chromosome is crossed over during Meiosis to create new combinations of code on each chromosome.
Following that, during fertilization, haploid cells (produced by a male and female) fuse to form a cell with two copies of each chromosome, known as a zygote.
Aneuploidy, which refers to an abnormal number of chromosomes, can cause an abnormal condition during the process of meiosis.
This condition is the most common cause of miscarriage and the genetic cause of developmental disabilities.
Mitosis:
Mitosis is the process by which cells divide. It is a stage of the cell cycle in which newly formed DNA is separated, resulting in the formation of two new cells with the same number and type of chromosomes as the parent nucleus.
Except for germ cells, most eukaryotic cells divide in a way that maintains the ploidy or number of chromosomes constant.
Mitosis is the process by which an organism's body fills with cells during growth and development.
Mitosis replaces worn-out and old cells with new cells throughout its life. The mitotic division is a type of reproduction in which new individuals are added to the population of single-celled eukaryotes.
The primary goal of mitosis is to ensure that each daughter cell formed has an entire and perfect set of chromosomes.
This does not work properly if the cells have too many or too few chromosomes.
