This diagram covers The Four Stages of Mitosis within Mitosis and the Cell Cycle for GCSE Biology. Cell division by mitosis, cell cycle phases, chromosome behavior, cytokinesis differences, stem cells, cancer, and practical investigations It is section 7 of 19 in this topic. Focus on the labels, the relationships between parts, and the explanation that turns the diagram into an exam-ready answer.
Topic position
Section 7 of 19
Practice
18 questions
Recall
18 flashcards
🧬 The Four Stages of Mitosis
1️⃣ Prophase
Key Events:
- Chromosomes condense and become visible under microscope
- Each chromosome consists of two identical chromatids
- Chromatids joined at the centromere
- Nuclear envelope (membrane) starts to break down
- Centrioles move to opposite poles in animal cells
2️⃣ Metaphase
Key Events:
- Chromosomes line up at the cell's equator (middle)
- Spindle fibers attach to centromeres
- Nuclear envelope has completely disappeared
- Cell checkpoint ensures all chromosomes are attached
3️⃣ Anaphase
Key Events:
- Chromatids separate and move to opposite poles
- Spindle fibers shorten and pull chromatids apart
- Each pole gets identical sets of chromosomes
- Cell begins to elongate
4️⃣ Telophase
Key Events:
- Two new nuclear envelopes form around each set of chromosomes at opposite poles
- Chromosomes start to uncoil and become less visible
- Spindle fibers break down
- Two genetically identical nuclei are formed
Quick Check: What is the difference between a chromatid and a chromosome?
A chromosome is a structure made of DNA. After DNA replication, each chromosome consists of two identical copies called chromatids, joined together at the centromere. So a duplicated chromosome = two chromatids. After anaphase, when the chromatids separate, each one becomes an individual chromosome in the daughter cell.