The combination of male sperm and female egg give rise to an embryo which is carried forward the process of reproduction. The sex of the child is decided by the combination of chromosomes. A woman’s body comprises of only XX chromosomes whereas the male body secretes XY chromosomes. The combination of X of woman and Y of man forms a male fetus whereas, the combination of X chromosome of woman and also from man forms female fetus. When these two (egg and sperm) meet zygote is formed.
Time factor plays an important role in the formation of embryo or the zygote. A zygote is formed when sperm and the egg meet. Both the egg and sperm are haploid cells which mean that both of them comprise of half number of chromosomes as compared to the measure present in their parents. When these two haploid cells meet, they form a diploid zygote consisting complete set of chromosomes. After that zygote starts dividing several times and grows into fallopian tubes. This zygote moves down through the fallopian tubes till it enters the uterus where it is implanted. When the zygote gets implanted inside the uterus, it turns into an embryo. Animals are not the only organisms that have been found to produce zygotes. Even fungi, flowering plants or ferns produce zygote as an immediate byproduct of fertilization.
A zygote can be seen only under microscope and has a size of an egg You do not have access to view this node. Even though the zygote divides fast, it does not grow in volume. The division helps it store more cells and help it to become hollow before it gets implanted in the lining of the uterus.
One of the most special characteristics of zygote is its ability to divide into two distinct masses of similar cells. Both these two identical cells move down the fallopian tubes and gets implanted into the uterine lining. When both these zygotes develop into an embryo, they can develop into identical twins. In case of fraternal twins, the two eggs separately combine with two different You do not have access to view this node and form separate zygotes which develop into independent fraternal embryos.
The gametes also known as sex cells comprise of haploid cells. Haploid cells are those cells which carry only one set of chromosome (23 chromosomes). So the human sperm and human egg are composed of 23 chromosomes respectively. The formation of these cells is caused due to the special cell division process called s meiosis. Due to this the progeny gets one chromosome set from the mother and one set from the father. When these two cells fertilize diploid zygote is formed which grows into diploid species. These diploid chromosomes each consist of inherited homologous two chromosome copies from mother and father. Excluding few species, almost all human organisms are known to be diploid organisms. The human diploid cells comprise of 46 chromosomes whereas haploid cells comprise of 23 chromosomes. The diploid cells are usually expressed as 2n = 2x while the human haploid cells are expressed as n. Here n= chromosome number and the x= monoploid number.