[Sophomore Biology at GHS: Cell Unit Notes] [Sophomore Biology]

Cell Theory

*1. All organisms composed of one or more cells.

*2. Cell is smallest living organizational unit.

*3. Cells arise only from division of other cells.

Types of Cells

1. Prokaryotic cells ------- 2. Eukaryotic cells

1) Prokaryotic cells: Bacteria & Blue-green Algae

Simplest organisms: Very small size.

Strong cell walls: resistant to environmental changes.

Lack membrane-bound organelles inside the cell.

No nucleus. (They have DNA)

Movement: Some can't move, while others have long threadlike flagella.

2) Eukaryotic cells: More modern, complex cells. Examples: Cells of Plants, Animals, & Fungi. 1) Cell membrane

2) Central nucleus containing DNA

3) Organelles with membranes in cytoplasm (like ER, vacuoles, mitochondria, etc.)