Each "human body cell" has 46 chromosomes. But human sex cells have 23 unpaired chromosomes in each cell. Sex cells are created by a special type of cell division, Meiosis. This pictures are showing, how sex cells sperm and egg or ovum are created by meiosis.
Sex cells have one set of chromosomes; body cells have two.
How sex is determined
In sexual reproduction, offspring arise from the union of specialized sex cells — a female egg and a male sperm. Just before the rediscovery of Mendel's work, careful studies were made of chromosome behavior during the formation of sex cells meiosis. First, homologous like chromosomes pair up at the cell equator where they actually exchange genetic information. Then, one chromosome from each pair is pulled toward each pole. At the end of this reduction division, each daughter cell receives only one homologous chromosome from each pair, ending up with one set.
Let's look at human chromosomes. This is a photomicrograph of stained human chromosomes from one body cell. How many chromosomes are there? No, count again. No, try again.
This page has been archived and is no longer updated. Diploid describes a cell that contain two copies of each chromosome. Nearly all the cells in the human body carry two homologous, or similar, copies of each chromosome. The only exception is cells in the germ line, which go on to produce gametes, or egg and sperm cells. Germ line cells are haploid, which means they contain a single set of chromosomes. In diploid cells, one set of chromosomes is inherited from the individual's mother, while the second is inherited from the father. Humans have 46 chromosomes in each diploid cell. Among those, there are two sex-determining chromosomes, and 22 pairs of autosomal, or non-sex, chromosomes.