What is Mitosis?
Mitosis is the division of a eukaryotic cell nucleus to form two identical daughter nuclei—essential for growth, repair and asexual reproduction. During mitosis, chromosomes condense, align at the cell's equator, separate and move to opposite poles, ensuring each daughter cell receives an identical set of genetic material.
Mitosis is nuclear division in four stages: Prophase (chromosomes condense, spindle forms), Metaphase (chromosomes align at metaphase plate), Anaphase (sister chromatids separate), Telophase (nuclei reform). Cytokinesis (cytoplasm division) follows, producing two genetically identical diploid cells.
- 1.Prophase — Chromosomes condense (visible); centrioles move to poles; spindle fibres form from centrosomes.
- 2.Metaphase — Chromosomes align at the metaphase plate (cell's equator); spindle fibres attach to kinetochores.
- 3.Anaphase — Sister chromatids separate; chromatids (now chromosomes) move to opposite poles; cell elongates.
- 4.Telophase — Nuclear envelopes reform around each pole; chromosomes decondense; cell prepares for cytokinesis.
Step-by-step worked examples
A human skin cell (2n = 46) undergoes mitosis. How many chromosomes are in each daughter cell?
Parent cell: 2n = 46 chromosomes After mitosis: two daughter cells, each 2n = 46 Identical diploid cells
At what stage do sister chromatids separate during mitosis?
Anaphase Sister chromatids (held at centromere) separate Chromatids are now independent chromosomes They move to opposite poles
Why is mitosis important for growth in a multicellular organism?
Mitosis produces identical copies Cells divide to increase tissue mass Example: skin cells divide thousands per minute
Flashcards
Quick quiz
Q1.During which phase do chromosomes first become visible under a microscope?
Q2.Chromosomes align at the cell's equator during:
Q3.A diploid cell (2n = 20) completes mitosis. Each daughter cell has:
Q4.Cytokinesis is:
The full card deck, worked steps and AI-tutor support for “What is Mitosis?” are in Notek — study by hand before your exam.
Common mistakes
Mitosis produces gametes. — Correct: Mitosis produces identical somatic (body) cells; meiosis produces gametes.
Daughter cells from mitosis are haploid. — Correct: Daughter cells are diploid (identical to parent).
Cytokinesis is part of mitosis. — Correct: Mitosis is nuclear division; cytokinesis (cytoplasm division) follows and is separate.
Centrioles are present in all eukaryotic cells. — Correct: Centrioles are present in animal cells; plant cells lack centrioles.
FAQ
What is the purpose of mitosis?
Growth, repair, and asexual reproduction—to produce two identical daughter cells from one.
How many times does a cell divide during mitosis?
Once: one parent cell → two daughter cells (one division event).
Is mitosis the same in animal and plant cells?
Mostly yes, but plant cells lack centrioles and form a cell plate (not cleavage furrow) during cytokinesis.
What would happen if mitosis failed to complete?
The cell would be unable to divide, potentially triggering cell death or (if safety checks fail) uncontrolled division (cancer).