CELLS
1. **Cell Theory**:
- Proposed by Schleiden and Schwann in 1839.
- All living organisms are composed of one or more cells.
- The cell is the basic unit of structure, function, and organization in all
organisms.
- Cells arise from pre-existing cells through division.
2. **Types of Cells**:
- Prokaryotic Cells:
- Lack a membrane-bound nucleus.
- Examples include bacteria and archaea.
- Eukaryotic Cells:
- Have a membrane-bound nucleus and organelles.
- Found in plants, animals, fungi, and protists.
3. **Cell Structure**:
- **Plasma Membrane**:
- Outer boundary of the cell, composed of a phospholipid bilayer.
- Regulates the passage of substances in and out of the cell.
- **Nucleus**:
- Contains the cell's genetic material (DNA).
- Controls cell activities and gene expression.
- **Cytoplasm**:
- Gel-like substance inside the cell.
- Contains organelles and cytosol.
- **Organelles**:
- Structures with specific functions:
1. **Cell Theory**:
- Proposed by Schleiden and Schwann in 1839.
- All living organisms are composed of one or more cells.
- The cell is the basic unit of structure, function, and organization in all
organisms.
- Cells arise from pre-existing cells through division.
2. **Types of Cells**:
- Prokaryotic Cells:
- Lack a membrane-bound nucleus.
- Examples include bacteria and archaea.
- Eukaryotic Cells:
- Have a membrane-bound nucleus and organelles.
- Found in plants, animals, fungi, and protists.
3. **Cell Structure**:
- **Plasma Membrane**:
- Outer boundary of the cell, composed of a phospholipid bilayer.
- Regulates the passage of substances in and out of the cell.
- **Nucleus**:
- Contains the cell's genetic material (DNA).
- Controls cell activities and gene expression.
- **Cytoplasm**:
- Gel-like substance inside the cell.
- Contains organelles and cytosol.
- **Organelles**:
- Structures with specific functions:
