MITOSIS & MEIOSIS
🧬 Introduction to Mitosis
Mitosis is a special process that cells use to make copies of themselves. It helps living things grow, heal, and stay healthy. Every time you grow taller or heal a cut, mitosis is working behind the scenes!
🔍 Explanation of Mitosis
Mitosis happens in five main steps:
- Interphase – The cell gets ready by copying its DNA.
- Prophase – The DNA forms into visible chromosomes.
- Metaphase – Chromosomes line up in the middle of the cell.
- Anaphase – Chromosomes split and move to opposite sides.
- Telophase – Two new nuclei form, and the cell starts to divide.
After these steps, the cell finishes with cytokinesis, where it splits into two identical cells.
📝 Summary
- Mitosis creates two identical cells.
- It’s used for growth, repair, and replacing old cells.
- Only body cells (not sperm or egg cells) use mitosis.
🌱 Introduction to Meiosis
Meiosis is a special kind of cell division that helps living things reproduce. It creates sex cells—like sperm in boys and eggs in girls. These cells are different from regular body cells because they have half the number of chromosomes.
🔍 Explanation of Meiosis
Meiosis happens in two rounds of cell division:
🌀 Meiosis I
- Chromosomes pair up and swap pieces (this is called crossing over).
- The cell splits into two new cells, each with half the chromosome pairs.
🌀 Meiosis II
- The two cells divide again.
- This time, the chromatids (the halves of each chromosome) separate.
- Now we have four cells, each with half the chromosomes of the original cell.
These cells are not identical—they’re all a little different, which helps create genetic variety in living things.
📝 Summary
- Meiosis makes four unique sex cells.
- Each has half the DNA of the original cell.
- It’s important for sexual reproduction and genetic diversity.
⚖️ Comparison: Mitosis vs. Meiosis
| Feature | Mitosis | Meiosis |
|---|---|---|
| Number of cells made | 2 identical cells | 4 different cells |
| Type of cells | Body cells (somatic) | Sex cells (sperm/egg) |
| Purpose | Growth and repair | Reproduction |
| Chromosome count | Same as original cell | Half of original cell |
| Genetic result | Identical to parent | Different from parent |
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