Sperm in males and egg cells in females When a haploid sperm and a haploid egg fuse during fertilization, their single sets of chromosomes combine, restoring the diploid chromosome number in the newly formed zygote. Meiosis, division of a germ cell involving two fissions of the nucleus and giving rise to four gametes, or sex cells, each with half the number of chromosomes of the original cell The process of meiosis is characteristic of organisms that reproduce sexually and have a diploid set of chromosomes in the nucleus. The final result of meiosis is four sex cells, each with half the number of chromosomes of the original parent cell Each cell has only one chromosome from each original homologous pair.
The daughter cells are haploid (n), having half of the chromosome number of the original cell, which is diploid (2n) Meiosis produces sex cells, while mitosis replicates cells from growth and repair. In each cell that undergoes meiosis, the arrangement of the chromosomes is different There are two possibilities for orientation (for each pair) Thus, the possible number of alignments equals 2 n where n is the number of chromosomes per set Humans have 23 chromosome pairs, which results in over eight million (2 23) possibilities.
In fertilization, an egg cell and a sperm cell combine These sex cells are also called reproductive cells or gametes Sperm cells are produced in men's testicles and egg cells are produced in women's ovaries Sex cells are different from other cells in one special way Put simply, they only have one half of the total amount.
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