The significance of mitosis
Why mitosis matters
- Mitosis is nuclear division that makes two genetically identical daughter cells.
- Identical copies are exactly what a body needs to grow and repair itself.
- But the same process, out of control, causes tumours.
Practice
The two daughter cells produced by mitosis are:
Mitosis produces genetically identical cells — they carry exactly the same genes as the parent.
What mitosis is for
- growth of a multicellular organism (more cells).
- replacement of dead or damaged cells.
- repair of tissues by making new cells.
- asexual reproduction — one parent producing identical offspring.
Each new cell carries exactly the same genes as the parent.
Practice
Which of these is a role of mitosis?
Mitosis underlies growth, replacement of cells, tissue repair, and asexual reproduction — all needing identical cells.
Stem cells
- A stem cell is an unspecialised cell that can:
- keep dividing by mitosis, and
- differentiate (change) into specialised cell types.
- They are the source of new cells for replacing losses and repairing tissues.
Practice
A stem cell is best described as a cell that:
Stem cells are unspecialised; they keep dividing by mitosis and can differentiate into specialised cells.
When control is lost
- The cell cycle is normally tightly controlled, so cells divide only when needed.
- If that control is lost, a cell divides again and again without stopping.
- This uncontrolled division produces a lump of cells — a tumour.
Practice
A tumour forms when:
Losing cell-cycle control lets cells divide without stopping, building up into a tumour.
You've got it
Key idea
- mitosis → two genetically identical daughter cells (same genes)
- used for growth, replacement, repair, asexual reproduction
- stem cell = unspecialised; divides by mitosis and differentiates
- losing cell-cycle control → uncontrolled division → a tumour