38. Mitosis and meiosis are two different ways cells divide. They both share common characteristics and processes, but differ in some very important ways.
a. What are the end products of the two processes? How do they differ from the original or "parent" cell, if at all?
In the end of mitosis, each nucleus ends up with the same number and kinds of chromosomes as the original cell. In the end of meiosis, a nuclear envelope forms around each set of chromosomes. The spindle breaks down, and the cell undergoes cytokinesis. The result of meiosis is four haploid cells.
b. Explain the major differences between the two processes that result in the different end products. In which process does chromosomal exchange occur?
During mitosis, spindle fibers drag the chromatids to opposite poles of the cell. A nuclear envelope forms. Each resulting nucleus contains a copy of the original cell's chromosomes. On the other hand, during meiosis I, homologous chromosomes separate. During meiosis II, the two chromatids of each chromosome separate. As a result of meiosis, 4 haploid cells are produced from one diploid cell. Chromosomal exchange occurs during meiosis.
Are my answers OK?
Biology - bobpursley, Friday, February 12, 2010 at 1:55pm
Exactly right for diploids. Some day grab a genetics book and look up the processes for tripolids (mainly salamanders, and trout) and quadraploids (mainly occuring in tobacco, inbred plants, a species of rats in China, and in "seedless" fruits.
Biology - mysterychicken, Friday, February 12, 2010 at 2:15pm