Ssc Biology Chapter 2 Hand Note Exclusive

SSC Biology Chapter 2, Cells and Tissues of Organisms, focuses on the fundamental structures that make up living things and how they organize to perform life functions. 1. The Living Cell

• Protoplasm: living substance inside the cell
• Organelle: specialized structure within a cell
• Chromosomes: thread-like structures carrying genetic information

📌 Exclusive Tip for SSC 2026+:

1. The atomic model has evolved over time, from Thomson's to Rutherford's to Bohr's model.
2. The nucleus of an atom contains protons and neutrons, while electrons occupy energy levels around the nucleus.
3. Atomic number and mass number are used to identify and classify elements.

🔍 2. Prokaryotic vs. Eukaryotic Cells (প্রোকারিওটিক ও ইউকারিওটিক)

| Feature | Prokaryotic | Eukaryotic | | :--- | :--- | :--- | | Nucleus | No true nucleus (Nucleoid) | True nucleus with membrane | | Organelles | Only ribosomes | All organelles (Mitochondria, ER, etc.) | | Size | 1-10 µm | 10-100 µm | | Example | Bacteria, Cyanobacteria | Plants, Animals, Fungi | ssc biology chapter 2 hand note exclusive