The outer most boundary of cell in plants, fungi, algae, and bacteria is cell wall. The cell wall of the plant cell is different from that of prokaryotes (bacteria and cynobacteria) and fungi both in structure and chemical composition. Cell wall is dead but the protoplasm of cell secretes it. Its thickness varies in different cells of the plant.
Structure
Cell wall is made up of following three layers:
Structure
Cell wall is made up of following three layers:
Middle lamella
Primary wall
Secondary Wall
Middle Lamella:
The middle lamella is first to be formed n between the primary walls of the neighboring cells. Pectin is especially abundant in middle lamella. It is actually a layer of adhesive substances, which holds the cells together.
Primary wall:
It is made up of cellulose and some deposition of pectin and hemicellulose. Cellulose molecules are arranged in a criss cross arrangement. The primary wall is a true wall and develops in newly growing cells.
Secondary Wall:
It is formed inner to primary wall and is comparatively thick and rigid. Chemically it is made up of inorganic salts, silica, waxes, cutin and lignin etc.
Prokaryotic cell wall:
It lacks cellulose. Its strengthening material is peptidoglycan or murein. Fungal cell wall is made up of chitin.
Functions:
Cell wall is very important structure. It provides a definite shape to the cell and keeps it rigid. It does not act as barrier to the materials passing through it.
Structure
Cell wall is made up of following three layers:
Structure
Cell wall is made up of following three layers:
Middle lamella
Primary wall
Secondary Wall
Middle Lamella:
The middle lamella is first to be formed n between the primary walls of the neighboring cells. Pectin is especially abundant in middle lamella. It is actually a layer of adhesive substances, which holds the cells together.
Primary wall:
It is made up of cellulose and some deposition of pectin and hemicellulose. Cellulose molecules are arranged in a criss cross arrangement. The primary wall is a true wall and develops in newly growing cells.
Secondary Wall:
It is formed inner to primary wall and is comparatively thick and rigid. Chemically it is made up of inorganic salts, silica, waxes, cutin and lignin etc.
Prokaryotic cell wall:
It lacks cellulose. Its strengthening material is peptidoglycan or murein. Fungal cell wall is made up of chitin.
Functions:
Cell wall is very important structure. It provides a definite shape to the cell and keeps it rigid. It does not act as barrier to the materials passing through it.
