The document summarizes the components and composition of plant cell walls. It discusses that plant cell walls are composed of three layers: the middle lamella, primary cell wall, and secondary cell wall. The middle lamella is a pectin layer that cements adjoining cells together. The primary cell wall is a thin, flexible layer composed of pectin, hemicellulose, and glycoprotein. The secondary cell wall is extremely rigid and provides strength, composed of cellulose, hemicellulose, and lignin.

1. Cell Wall : Components and
Composition

2. What is cell wall ?
• The cell wall is the tough, usually flexible but
sometimes fairly rigid layer that surrounds
cells.
• It is located outside the cell membrane.
• It’s main function is to provide cells rigidity,
strength and protection and also acting as a
filtering mechanism.

3. Composition of Plant Cell Wall
• In the primary plant cell wall, the major
carbohydrates are cellulose, hemicellulose
and pectin.
• The outer part of the primary cell wall of the
plant cell wall is made of wax and cutin and is
known as plant cuticle.
• The secondary cell wall contains cellulose,
xylan, lignin. And one type of hemicellulose.

4. Composition of Plant Cell Wall
• Cell wall of epidermis, endodermis contain
suberin.
• Plant cell walls also contain enzymes such as
hydrolases, esterases, peroxidase and
transglysolases.
• They can also contain mineral substances.

5. Components of Plant Cell Wall
Plant cell wall composed of three layers.
1. The middle lamella
2. The primary cell wall
3. The secondary cell wall

6. Plant Cell Wall Structure

7. The Middle Lamella
• The middle lamella is a pectin layer.
• It cements the cell walls of two
adjoining cells together.
• It is the first layer formed during cell division.

8. The Primary Cell Wall
• It is formed after the middle lamella.
• A thin, flexible and extensible layer .
• It is formed while the cell is growing.
• It is composed of pectin compounds,
hemicellulose and glycoprotein.
• The layer consists of a framework of cellulose
microfibrils.

9. The Secondary Cell Wall
• It is extremely rigid and provides strength.
• It is not found in all cell types.
• It is composed of cellulose, hemicellulose and
lignin.

10. The End