Friday, May 14, 2010

Mitosis and Meiosis



Image shows karyotype of a female. Her somatic cell has a diploid number of 46.

refer to your chapter 5 note.
What is diploid number & haploid number of chromosome?
1. Diploid - organisms or cells that have 2 sets of chromosomes.
2. Haploid - cells that have only one set of chromosomes.

Here are some images which are related to cell division:

1. Image below shows the chromosomes, DNA, histone proteins inside the nucleus of a typical cell.




2. Image below shows chromosomes.
  • When the chromosome condense, coil-up and tighten during prophase of mitosis (or prophase I or prohase II of meiosis), the chromosome appear as two identical chromatids called sister chromatids attached together at the contromere.



3. Prophase I of meiosis I.
  • At the chiasma, exchange of genetic material between the non-sister chromatids of bivalent through the process of crossing over.
  • Crossing over results in new combination of genetic material and is important source of genetic variation.




4. the differences between Meiosis & Mitosis