Chromosome behaviour in mitosis
Introduced| English | Meaning |
|---|---|
| cytokinesis/ˌsaɪtəkəˈniːsɪs/ | The division of a cell's cytoplasm to form separate daughter cells. |
| prophase/ˈprɒfeɪz/ | Chromosomes condense, nuclear envelope breaks, spindle forms. |
| metaphase/ˌmetəˈfeɪz/ | Line up at the equator. |
| nuclear envelope/ˈnjuːklɪə ˈenvələʊp/ | The double membrane surrounding the nucleus of a eukaryotic cell. |
| spindle/ˈspɪndl/ | A structure of microtubules that attaches to and separates chromosomes during cell division. |
| anaphase/ˈænəfeɪz/ | The division stage when homologous chromosomes separate in meiosis I, or sister chromatids separate in mitosis and meiosis II. |
| telophase/ˈteləfeɪz/ | Two new nuclei. |
The four stages of mitosis
- Mitosis runs through four stages — remember them in order: P · M · A · T.
- In each, the chromosomes do something you can recognise under a microscope.
- After mitosis, the whole cell splits in cytokinesis 胞质分裂.
Prophase 前期 and metaphase 中期
- Prophase: chromosomes coil up and become visible (as two sister chromatids); the nuclear envelope 核膜 breaks down; a spindle 纺锤体 of fibres forms.
- Metaphase: chromosomes line up along the middle (the equator); spindle fibres attach to each centromere.
A replicated chromosome with two sister chromatids
The stages of mitosis
Drag through prophase, metaphase, anaphase and telophase to watch the chromosomes line up and then separate into two identical cells.
In prophase:
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Prophase: chromosomes coil up and become visible, the nuclear envelope breaks down, and the spindle forms.
In ______, the chromosomes line up along the equator of the cell.
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In metaphase the chromosomes line up at the cell's equator and spindle fibres attach to each centromere.
Match each stage of mitosis to what happens.
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PMAT: prophase → metaphase → anaphase → telophase.
Anaphase 后期 and telophase 末期
- Anaphase: the centromeres split, and the sister chromatids are pulled to opposite poles of the cell.
- Telophase: a full set of chromosomes reaches each pole; a new nuclear envelope forms around each set, giving two nuclei.
The four stages of mitosis
The stages of mitosis
Step through PMAT. Watch the chromosomes condense, line up, split to the poles, then reform two nuclei.
Anaphase is the stage where:
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In anaphase the centromeres split and the spindle pulls the sister chromatids apart to the poles.
In anaphase, whole chromosomes (not separated chromatids) move to each pole.
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The centromeres split first, so it is the separated sister chromatids that are pulled to each pole.
Put the stages of mitosis in the correct order.
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PMAT: Prophase → Metaphase → Anaphase → Telophase.
Cytokinesis
- The cytoplasm now divides:
- in an animal cell, the membrane pinches inwards to split the cell.
- in a plant cell, a new cell wall forms across the middle.
- The result: two genetically identical daughter cells.
How does cytokinesis differ between animal and plant cells?
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Animal cells split by the membrane pinching in; plant cells build a new cell wall across the centre.
You've got it
- order: Prophase → Metaphase → Anaphase → Telophase (PMAT)
- prophase: chromosomes condense, nuclear envelope breaks, spindle forms
- metaphase: line up at the equator; anaphase: centromeres split, chromatids to poles
- telophase: two new nuclei; then cytokinesis (animal pinches, plant new wall)