What Are Living Organisms Made Up Of?
Key Notes:
🔬 Living Organisms Are Made of Cells
The cell is the basic structural and functional unit of life.
All living organisms are made up of one or more cells.
- Unicellular organisms: Made of a single cell (e.g., Amoeba, Bacteria).
- Multicellular organisms: Made of many cells (e.g., Humans, Plants).
🧱 Components Inside a Cell
- Cell Membrane: Outer covering; controls what enters and exits the cell.
- Cytoplasm: Jelly-like substance where cell activities happen.
- Nucleus: The “control center” of the cell; contains genetic material (DNA).
- Organelles: Small parts inside cells that perform specific functions (e.g., mitochondria, ribosomes).
🌱 Difference Between Plant and Animal Cells
| Feature | Plant Cell | Animal Cell |
|---|---|---|
| Cell Wall | Present (gives shape & support) | Absent |
| Chloroplast | Present (for photosynthesis) | Absent |
| Vacuole | Large central vacuole | Small or absent |
| Shape | Generally rectangular | Generally round or irregular |
🧬 Cells Contain Biomolecules
Cells are made up of four main types of biomolecules:
- Carbohydrates – Provide energy (e.g., glucose).
- Proteins – Build body tissues and perform functions.
- Fats (Lipids) – Store energy and form cell membranes.
- Nucleic Acids (DNA & RNA) – Carry genetic information.
🧪 Levels of Organization in Living Things
- Cells →
- Tissues (group of similar cells) →
- Organs (group of tissues) →
- Organ systems (group of organs) →
- Organism
🧠 Quick Facts
- The discovery of cells was made by Robert Hooke in 1665.
- The study of cells is called Cytology.
- The cell theory was given by Schleiden and Schwann.
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