Cell wall

Definition

A cell wall is a rigid layer that surrounds the cells of plants, fungi, bacteria, and archaea. It provides structural support and protection while also determining the shape of the cell.

5 Must Know Facts For Your Next Test

1. Plant cell walls are primarily composed of cellulose, hemicellulose, and lignin.
2. Bacterial cell walls contain peptidoglycan, which is essential for their structural integrity.
3. Archaea have unique cell wall compositions that lack peptidoglycan but may contain pseudopeptidoglycan or other polymers.
4. Fungal cell walls are made primarily of chitin.
5. The absence or presence of a cell wall helps differentiate between Gram-positive and Gram-negative bacteria through Gram staining.

Review Questions

• What are the main components of plant cell walls?
• How do bacterial and archaeal cell walls differ?
• What role does the cell wall play in maintaining the shape and integrity of a cell?

Related terms

Plasma Membrane: A selectively permeable barrier that encloses the cytoplasm of a cell, controlling movement in and out.

Peptidoglycan: A polymer consisting of sugars and amino acids that forms a mesh-like layer outside the plasma membrane in bacteria.

Chitin: A long-chain polymer derived from glucose found in fungal cell walls and exoskeletons of arthropods.