The significance of mitosis
| English | Chinese | Pinyin |
|---|---|---|
| mitosis | 有丝分裂 | yǒu sī fēn liè |
| genetically identical | 遗传上相同 | yí chuán shàng xiàng tóng |
| tumour | 肿瘤 | zhǒng liú |
| asexual reproduction | 无性生殖 | wú xìng shēng zhí |
| stem cell | 干细胞 | gàn xì bāo |
| unspecialised | 未分化 | wèi fēn huà |
| differentiate | 分化 | fēn huà |
Why mitosis 有丝分裂 matters
- Mitosis is nuclear division that makes two genetically identical 遗传上相同 daughter cells.
- Identical copies are exactly what a body needs to grow and repair itself.
- But the same process, out of control, causes tumours 肿瘤.
Why mitosis matters
Classify real cases by the role mitosis is playing.
The two daughter cells produced by mitosis are:
Mitosis produces genetically identical cells — they carry exactly the same genes as the parent.
Mitosis produces genetically identical daughter cells, which is why it is used for growth and repair.
Identical copies are exactly what growth, repair and asexual reproduction need.
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 无性生殖 — one parent producing identical offspring.
Each new cell carries exactly the same genes as the parent.
The mitotic cell cycle: interphase then mitosis and cytokinesis
Select all the roles of mitosis.
Mitosis gives identical cells for growth, repair/replacement and asexual reproduction. Varied gametes come from meiosis; ATP comes from respiration.
Match each role of mitosis to an example.
All of these need genetically identical cells, so all use mitosis.
Stem cells 干细胞
- A stem cell is an unspecialised 未分化 cell that can:
- keep dividing by mitosis, and
- differentiate 分化 (change) into specialised cell types.
- They are the source of new cells for replacing losses and repairing tissues.
A stem cell can keep dividing or differentiate into many specialised cell types
A stained onion root tip: several cells are caught dividing
An unspecialised cell that can keep dividing and differentiate into other cell types is a ______ cell.
Stem cells are unspecialised; they divide 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.
When cell-cycle control is lost, a cell divides over and over, building up into a tumour
A tumour forms when:
Losing cell-cycle control lets cells divide without stopping, building up into a tumour.
You've got it
- 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