I will try to dummy it down for you.
Prophase is a stage of mitosis in which the chromatin (the DNA; recall that are 46 individual pieces of DNA in a human cell: 23 from mom and 23 from dad) condenses (becomes more dense) into a highly ordered structure called a chromosome in which the chromatin
becomes visible. So basically before this phase, the chromatin (the DNA) is so thin that you can't see it in a light microscope! Since the genetic material has been duplicated in an previous phase of the cell cycle, there are two identical copies of each chromosome in the cell (so 46 x 2 = 92 copies of the DNA or similarly (
23 x 2) + (
23 x 2) = 92). Identical chromosomes, called sister chromatids, are attached to each other at the centromere.
\/
/\ so basically during prophase, you will have 92 of these guys in a
human cell by the end of this phase. Each cross you see represents a single chromosome.
Metaphase, the next stage, is a stage of mitosis in which these condensed chromosomes align in the middle of the cell before being separated into each of the two daughter cells. There has to be similarity so that each new cell produced has an exact copy... 46 each.
Anaphase, the next stage, is the stage of mitosis when chromosomes separate. Each chromatid moves to opposite poles of the cell.
\/ BECOMES \ <== /
/\ / ==> \
\/ BECOMES \ <== /
/\ / ==> \
\/ BECOMES \ <== /
/\ / ==> \
.
.
.
92
Lastly, during telophase, the two daughter nuclei (nucleus') form in the daughter cells. The nuclear envelopes of the daughter cells are formed from the fragments of the nuclear envelope of the parent cell.
After you've reviewed this, watch this animation:
http://highered.mcgraw-hill.com/olcweb/cgi/pluginpop.cgi?it=swf::535::535::/sites/dl/free/0072437316/120073/bio14.swf::Mitosis%20and%20Cytokinesis
Reply back if you need further assistance.
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