State that new cells are produced by division of existing cells.

🧬 2.1 Cell Structure – Cambridge IGCSE Biology 0610

Objective: State that new cells are produced by division of existing cells.

🔬 What is a Cell?

A cell is the basic building block of all living things. Think of it as a tiny factory that carries out all the processes needed for life. Inside this factory, there are many specialised parts that work together.

• 🧱 Cell membrane – the factory walls that control what comes in and out.
• 🏭 Nucleus – the factory manager, holding the DNA blueprint.
• ⚙️ Organelles – specialised machines:
  • ⚡ Ribosomes – protein factories.
  • 🛢️ Endoplasmic reticulum – conveyor belts for proteins.
  • 🧪 Golgi apparatus – packaging and shipping centre.
  • 🔋 Mitochondria – power plants producing ATP.
  • 🧼 Lysosomes – waste disposal units.
  • 🌊 Chloroplasts (in plant cells) – solar panels for photosynthesis.
• 🧪 Cytoplasm – the jelly-like medium where all organelles float.

🛠️ Cell Division – Making New Cells

Just like a photocopy machine can produce a new copy from an existing document, a cell can produce a new cell by dividing itself. This process is called cell division.

1. 🔄 Interphase – the cell grows and copies its DNA. Think of it as the factory preparing all the materials for the next shift.
2. ⚛️ Mitosis – the DNA is split into two identical sets. Imagine the manager handing out identical blueprints to two new managers.
3. 🧩 Cytokinesis – the cytoplasm divides, creating two separate factories. Each new cell now has its own manager and machines.

Mathematically, one cell becomes two: $$1 \;\rightarrow\; 2$$ or, in general, a cell with $n$ chromosomes produces two cells each with $n$ chromosomes: $$n \;\rightarrow\; 2n$$

📊 Summary Table – Cell Division Phases

💡 Key Takeaways

• All living organisms are made of cells.
• A cell is a complex factory with specialised parts.
• New cells are produced by the division of existing cells, following the sequence: interphase → mitosis → cytokinesis.
• During division, the DNA is duplicated and equally distributed, ensuring each new cell has the same genetic information.