Cheek cells lack a cell wall because they are eukaryotic animal cells, which, unlike plant cells, fungi, and certain prokaryotes, do not possess this rigid outer layer. The absence of a cell wall in animal cells is a fundamental characteristic that differentiates them from other cell types.
Understanding Cell Structures
To understand why cheek cells lack cell walls, it's important to consider the differences between cell types:
Animal Cells vs. Plant Cells
| Feature | Animal Cells | Plant Cells |
|---|---|---|
| Cell Wall | Absent | Present (primarily cellulose) |
| Plasma Membrane | Flexible | Flexible, but inside the cell wall |
| Shape | Irregular/Variable | More defined, rigid |
| Purpose | Provides structure, cell communication | Support, protection, and cell shape |
Key Points about Cell Walls:
- Composition: Primarily made of cellulose in plant cells, chitin in fungi, and peptidoglycans in bacteria.
- Function: Provides structural support, protection, and maintains cell shape.
- Presence: Found in plants, fungi, and some prokaryotes (like bacteria), but notably absent in animal cells.
Why Cheek Cells Don't Need a Cell Wall
- Flexibility: Animal cells, including cheek cells, need a flexible plasma membrane to allow for varied shapes and movement, which cell walls would restrict.
- Function: Cheek cells do not require the rigid support provided by a cell wall as they primarily function in protection and lining the oral cavity.
- Adaptation: Animal cells have adapted other methods for support, such as the cytoskeleton, and rely on cell to cell adhesion for tissue structure and organization, negating the need for a cell wall.
Reference
The information provided is supported by the reference: "Cheek cells are eukaryotic animal cells, and animal cells lack cell walls. Instead, they have a flexible plasma membrane that allows for a variety of shapes and functions. Cell walls are characteristic of plant cells, fungi, and some prokaryotes (like bacteria), providing structural support and protection."
