Cells reproduce for 3 reasons
-Repair
-Growth
- And to make new kinds of cells
And how they reproduce
Scientists call the process of
somatic cell division mitosis. Mitosis has six distinct steps in which
the cell organizes and copies the DNA in the nucleus. Once copied, each
new cell has its own copy of the DNA. The six steps of mitosis are
prophase, prometaphase, metaphase, anaphase, telophase and cytokinesis.
Some authorities consider the non-dividing portion of the cell’s
lifecycle, known as interphase, to be one of seven steps involved in
mitosis; however, interphase cells are not actively dividing.
Sex cells, such as sperm or eggs, must divide differently. Sex cells
only possess one-half of the DNA that makes up a new animal. That way,
when they combine, the resulting organism gets half of its DNA from its
mother and half from its father. Because sex cells only want half of the
DNA in each cell, they go through a different division process called
meiosis. In meiosis, the cells split a second time, which yields four
daughter cells rather than two as with mitosis; however, this provides
each daughter cell with 23 chromosomes in contrast to the 46 chromosomes
in somatic cells.
