The Phases of Mitosis

The stage that the chromatin condenses into chromosomes is Prophase and during this first mitotic stage, the nucleolus fades and chromatin (replicated DNA and associated proteins) condenses into chromosomes. The stage that the chromosomes align in the center of the cell and tension is applied by the spindle fibers aligns all chromosomes in one plane at the center of the cell. The stage that is the longest part of the cell cycle is Interphase and this is the longest period of the complete cell cycle during which DNA replicates, the centrioles divide, and proteins are actively produced. The stage that the nuclear envelopes breaks down is Pro metaphase and in this stage the nuclear envelope breaks down so there is no longer a recognizable nucleus. The stage that the cell is cleaved into two new daughter cells is Cytokinesis and it is in this region that a contractile ring cleaves the cell into two daughter cells. Microtubules then reorganize into a new cytoskeleton for the return to interphase. The stage that the daughter chromosomes arrive at the poles is Telophase and the daughter chromosomes arrive at the poles and the spindle fibers that have pulled them apart disappear. There are 4 chromosomes visible at the beginning of mitosis. At the end of mitosis there will be 8 chromosomes in each daughter cell. The little green T shaped things on the cell are the Centrioles. During mitosis the centrioles are together in one cell and during they move around and at the end they are split up by themselves in one of the two daughter cells. The three stages below are phases of mitosis. The first stage is Metaphase. The second stage is Cytokinesis. The third stage is Prophase.

Prophase The chromosomes condense/ nucleus disappears/ the centrioles go to opposites sides of the cell/ and spindle network fiber forms.

Metaphase Spindle fibers attach to kinetochores / chromosomes align on meta phase plate.

Telophase Nuclear envelope reforms/ chromosomes disperse/ spindle fibers dissolve/ cytokinesis= the cell is pinched in two by ring of action protein

You will have 36 cells to classify. When you’re finished, record your data in the chart below.

	Interphase	Prophase	Metaphase	Anaphase	Telophase	Total
Number of cells	20	10	3	2	1	36
Percent of cells (calculate: number of cells divided by total cells x 100 )	55.5%	27.7%	8.3%	5.5%	2.7%	100 %

	View 1	View 2	View 3	View 4	View 5
Whitefish	telophase	metaphase	prophase	anaphase	wasn't a 5th view
Onion	anaphase	metaphase	prophase	interphase	telophase