Mitosis is one division that gives two cells identical to the parent. To put the stages in order, follow what the chromosomes are doing.
This lesson is part of cell division. Once it feels secure, sequencing meiosis uses the same habit with two divisions.
How do I follow the chromosomes?
Ask three questions about a diagram: are the chromosomes visible, where are they, and are the chromatids still joined? The answers fix the stage.
| Stage | Where are the chromosomes? | Key event |
|---|---|---|
| Prophase | Visible, scattered in the cell | Nuclear membrane breaks down, spindle forms |
| Metaphase | Lined up at the equator | Spindle fibres attach to centromeres |
| Anaphase | Moving to opposite poles | Sister chromatids separate |
| Telophase | At the two poles, uncoiling | Two nuclei form, cytoplasm divides |
Before all four, interphase replicates the DNA. Without that step, there would be nothing to separate.
Worked example: order four unlabelled diagrams
Question. Four diagrams show stages of mitosis in a cell with four chromosomes. Arrange them in order. (2 marks)
(W) chromosomes in a row across the middle; (X) two sets of chromosomes at opposite ends; (Y) chromosomes visible and scattered, nuclear membrane missing; (Z) chromatids being pulled apart, V-shaped.
Step 1. Y shows scattered chromosomes with no nuclear membrane, so it is prophase.
Step 2. W shows the row along the equator, so it is metaphase.
Step 3. Z shows chromatids moving apart, so it is anaphase.
Step 4. X shows two sets at the poles, so it is telophase.
Order: Y, W, Z, X.
The mistake that costs marks
The usual slip is to confuse prophase with metaphase because both show visible chromosomes. The key difference is arrangement, not appearance.
Scattered means prophase. A neat row means metaphase. Asking “where are they?” first stops the swap.
Check yourself
A cell with 8 chromosomes is in anaphase. How many chromosomes are at each pole, and how many in total in the cell at this moment?
Answer
Each pole receives 8 chromosomes, since each sister chromatid counts as a chromosome once it separates. In total the cell has 16 chromosomes at this moment.
After cytokinesis, each daughter cell has 8.
What to study next
Move on to sequencing meiosis and keep the same table habit. Then compare both processes in comparing chromosome and DNA changes. If you would like a teacher to watch you draw the stages, see online one-to-one Biology tuition.