Learning check
Once you have watched the video, check your learning with this quiz.
Mitosis is the process of cell division. After the DNA has been replicated in the S phase of the cell cycle, the cell enters mitosis.
- One cell → two cells
- o → 0 → 8 → oo 😉
After the DNA has been replicated, the cell enters mitosis.
Chromosomes, mitotic chromosomes, and sister chromatids
These concepts are easily confused:
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Don't confuse chromosomes, mitotic chromosome (metaphase chromosomes), and sister chromatids!
Interphase – S phase
- The DNA is copied (replicated).
- The centrosome is replicated.
The DNA and the centrosome are copied during the S-phase in the interphase.
Prophase
- The chromatin starts to condense (pack).
- Mitotic chromosomes are formed.
- Nuclear membrane dissolves.
- Centrosomes start to move away from each other.
Mitotic chromosomes become visible during prophase.
Structure of the (mitotic) chromosome
The DNA is wound two times around histones, and packed tightly into mitotic chromosomes.
The chromatin is very densely packed in mitotic chromosomes.
Metaphase
Nuclear membrane completely dissolved.
Mitotic chromosomes tightly packed, in the equatorial plane = metaphase plate.
- Complete mitotic spindle formed.
Metaphase.
Anaphase
Sister chromatids are pulled towards each pole.
Anaphase.
Telophase & cytokinesis
New nuclear membrane starts to form.
Chromosomes are unpacked again, relaxed chromatin forms.
Two new cells form ⇒ cytokinesis.
Telophase.
Cytokinesis.
