Re: what is meiosis in really really simple terms???

Jessica,

Don't dispair!  We'll get you through this.  You are right that every
human cell has 46 chromosomes except the sex-cells (egg and sperm).  Every
cell in your body has two sets of chromosomes - one set from your mother
and one from your father.  You have 2 chromosome 1's, 2 chromosome 2's,
2 chromosome 3's, .... up to 23.  In mitosis, where cells are replicated, 
the DNA replicates before mitosis. The copy and the copied DNA are held
together.  When it comes time to divide, the chromosomes line up, in a 
single line across the cell.  Then, the chromosome splits apart; one
strand of DNA going to one side of the cell and one to the other side.
Each strand of DNA is now called a chromosome so, each new cell has 46 
chromosomes.

Meiosis is divided into two parts; the first part (meiosis I)is where the 
chromosome number goes from 46 to 23 and the second part (meiosis II) which 
is very much like mitosis, where the cells with 23 chrmosomes are 
duplicated.  In meiosis I,  the like chromosomes pair up so you have 23 
pairs of chromosomes.  (The mother's chromosome 1 pairs up with the 
father's chromosome 1, the 2's pair, the 3's pair, etc.).  The pairs of 
chromosomes line up across the cell.  Then, the two chromosomes in 
each pair (each made up of 2 strands of DNA) separate and go to different 
sides of the cell.  You will then have two nuclei with 23 chromosomes; one 
chromosome 1, 1 chromosome 2, 1 chromosome 3, etc.  Then, in meiosis II,
the chromosomes divide just like in mitosis.

It is important to remember that all cells that aren't sex cells have two
sets of chromosomes.  Sex cells have one set of chromosomes.  When two
sex cells unite, the cell that results has two sets of chromosomes.

Sure hope this helps.