IB MYP Integrated Science- Biology - Cell division-Study Notes - New Syllabus
IB MYP Integrated Science- Biology – Cell division -Study Notes – New syllabus
IB MYP Integrated Science- Biology – Cell division -Study Notes -As per latest Syllabus.
Key Concepts:
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IB MYP Integrated Science -Concise Summary Notes- All Topics
Cell Division
🌱 Introduction
Cell division is the process by which one cell splits into two new cells. It helps organisms grow, repair damage, reproduce and maintain life.
- Mitosis – for growth and repair
- Meiosis – for producing gametes (sperm and egg)
🧬 Why Do Cells Divide?
- To repair damaged tissues
- For body growth
- To replace old or dead cells
- For asexual reproduction
- To produce gametes in sexually reproducing organisms
📌 Cell Cycle Overview
The cell cycle has three major parts:
- Interphase (longest phase)
- G1 – cell grows
- S – DNA is copied
- G2 – cell prepares for division
- M Phase – actual division (mitosis or meiosis)
- Cytokinesis – cytoplasm splits into two new cells
🧩 MITOSIS (Produces identical body cells)
Goal: One parent cell → two identical daughter cells
Used for growth, repair and replacement.
Phases of Mitosis
- Prophase – chromosomes condense, nuclear membrane disappears
- Metaphase – chromosomes line up in the center
- Anaphase – sister chromatids separate
- Telophase – two nuclei form, chromosomes uncoil
Cytokinesis – cell splits into two identical cells.
Key Features
- No crossing over
- Daughter cells are diploid
- Genetically identical cells
🧬 MEIOSIS (Produces gametes: sperm/egg)
Goal: One parent cell → four non-identical gametes
Main Features
- Two rounds of division: Meiosis I and II
- Gametes become haploid
- Genetic variation from:
- Crossing over
- Independent assortment
Steps in Short
- Meiosis I – homologous chromosomes separate
- Meiosis II – sister chromatids separate
Result: 4 unique haploid gametes
📊 Mitosis vs Meiosis
| Feature | Mitosis | Meiosis |
|---|---|---|
| Purpose | Growth, repair | Gamete formation |
| Number of cells | 2 | 4 |
| Type of cells | Body cells | Sex cells |
| Genetic variation | No | Yes |
| Chromosome number | Same as parent | Half of parent |
| Crossing over | No | Yes |
🧪 Importance of Cell Division
- Maintains chromosome number
- Allows reproduction
- Heals wounds
- Creates variation (through meiosis)
- Helps organisms grow from a fertilized egg
📦 Quick Recap
Cell division forms new cells for growth, repair and reproduction.
Interphase prepares the cell and copies DNA.
Mitosis → 2 identical cells.
Meiosis → 4 unique gametes.
Variation comes from crossing over and independent assortment.
Cytokinesis fully splits the cell into daughter cells.