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Mitosis and the cell cycle
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Your body makes millions of new cells every day. Mitosis is how one cell becomes two identical cells.
The cell cycle
In interphase the cell grows, makes more organelles and copies its DNA.
Then mitosis divides the nucleus, and cytokinesis splits the cytoplasm to make two cells.
Then mitosis divides the nucleus, and cytokinesis splits the cytoplasm to make two cells.
Stages of mitosis
Prophase: chromosomes condense and become visible. The nuclear membrane breaks down.
Metaphase: chromosomes line up across the middle of the cell.
Anaphase: the copies (chromatids) are pulled to opposite ends.
Telophase: new nuclear membranes form around each set.
Metaphase: chromosomes line up across the middle of the cell.
Anaphase: the copies (chromatids) are pulled to opposite ends.
Telophase: new nuclear membranes form around each set.
Why mitosis matters
Mitosis makes two genetically identical diploid cells. In humans each has 46 chromosomes.
It is used for growth, repair and asexual reproduction.
Cancer is the result of uncontrolled cell division.
It is used for growth, repair and asexual reproduction.
Cancer is the result of uncontrolled cell division.
A human skin cell divides by mitosis. How many chromosomes does each new cell have?
- Human body cells are diploid with 46 chromosomes.
- Mitosis makes identical copies, so the number stays the same.
- Each new cell has 46 chromosomes.
Answer: 46
Interphase copies the DNA. Mitosis (prophase, metaphase, anaphase, telophase) then cytokinesis make two genetically identical diploid cells for growth and repair.
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