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Mitosis & Meiosis

Chromosomes
1. Consist of DNA wrapped around a complex protein scaffold
2. Eukaryotic chromosomes are made of chromatin which is a complex of DNA and proteins
3. Dynamic pieces of chromatin that can alternate between tight and loose compaction. Highly compacted during cell division
4. Consist of 2 genetically identical sister chromatids after S-phase
Mitosis involves separation of identical sister chromatids
Only germ-line cells undergo meiosis
Meiosis I
1. Prophase I
  1. Chromosomes begin to condense
    1. Homologous chromosomes form pairs. Each pair is called a bivalent or tetrad.
      1. Crossing over between homologous chromosomes occurs
        After crossing over, the sister chromatids are no longer genetically identical
2. Metaphase I
  1. Paired chromosomes align on the equatorial plane in the cell
3. Anaphase I
  1. Homologous chromosomes separate and move to opposite sides
4. Telophase I
  1. Chromosome movement is completed and new nuclei begin to form
Meiosis II
1. Prophase II
  1. Chromosomes condense and become attached to spindle fibres
2. Metaphase II
  1. Chromosomes align on the equatorial plane in each cell
3. Anaphase II
  1. Sister chromatids disjoin and move to opposite poles in each cell
4. Telophase II
  1. Chromosomes condense and nuclei form
5. Cytokinesis
  1. The haploid daughter cells are separated by cytoplasmic membranes

Mitosis & Meiosis

	Created by clairegillian95 about 10 years ago