Mitosis

The five steps of mitosis, called prophase, prometaphase, metaphase, anaphase, and telophase, constitute the period in which the cell makes preparations for cell division. The five phases are differentiated by specific events of preparation for cell division. Cytokinesis refers to the actual cleavage event, splitting the cell in two.

Mitosis is the splitting and duplication of a cell. Mitosis makes 2 daughter cells, both containing 46 chromosomes.

PROPHASE

Meiosis

MEIOSIS

 

Meiosis is the reduction-division of the chromosomes

- gametes (sex cells)

- haploid [4 daughter cells] = 23 chromosomes each

 

PROCESS OF MEIOSIS

1. Interphase

2. Meiosis I

   * Prophase I - Finds its homologous pair/crossing over occours

   * Metaphase I - Lines up down the "middle" with its tetrad

   * Anaphase I - Split tetrad and they move away from one another

   * Telophase I - Begins to pinch inward to make 2 new cells & nucleus re-forms (cytokinesis)

   * Cytokinesis - Splitting of the cell

3. Meiosis II

   * Prophase II - Nucleus dissolves, spindle fibers form; chromosomes condense

   * Metaphase II - Line up down the middle

   * Anaphase II - Splits the chromatids at the centromere

   * Telophase II - Cells begin to pinch inwards/nucleus reforms

   * Cytokinesis - Splitting of the cell

 

 

Example of crossing over and tetrad