University:
Cameron University
Course:
1004 | General Biology
Academic year:

2019
Views:

250

Pages:

1
Author:

Clint W.

Stages of Mitosis Stage Diagram Key Events Before: Interphase (2n) After: S phase • DNA is uncondensed (chromatin) • DNA is replicated (S phase) to form genetically identical sister chromatids • Cell grows in size and organelles are duplicated (G1 and G2) Prophase (2n) Nuclear membrane dissolves • DNA supercoils and condenses (forms visible chromosomes) Centrosomes move to poles • Centrosomes move to poles and begin to produce spindle fibres • Centrosome spindle fibres attach to the centromere of each chromosome Spindle fibres • Spindle fibres contract and move the chromosomes towards the cell centre Metaphase (2n) M = Middle Chromatids • Chromosomes form a line along the equator (middle) of the cell • Spindle fibres continue to contract • Sister chromatids separate and move to opposite sides of the cell Anaphase (2n → 4n) A = Apart Telophase (4n) • Nuclear membrane dissolves Nuclear membranes reform • Sister chromatids are now regarded as two separate chromosomes • Chromosomes decondense (DNA forms chromatin) • Nuclear membranes form around the two identical chromosome sets • Cytokinesis occurs concurrently • Cytoplasmic division occurs to divide the cell into two daughter cells Cytokinesis (2n × 2) • Each daughter cell contains one copy of each identical sister chromatid • Daughter cells are genetically identical