Plant Cell Wall Structure

What is the primary function of the middle lamella in plant cells?

What type of polysaccharides are found in the primary cell wall?

What is the purpose of the secondary cell wall in plant cells?

What is unique about the composition of some secondary cell walls?

What is the sequence of layers in the plant cell wall, from outermost to innermost?

Which of the following plant cells do not have a secondary cell wall?

Plant Cell Wall Structure

The plant cell wall is multi-layered, consisting of up to three sections: middle lamella, primary cell wall, and secondary cell wall.
Not all plant cells have a secondary cell wall, but all have a middle lamella and primary cell wall.

Middle Lamella

Outermost layer of the cell wall, containing polysaccharides called pectins.
Pectins aid in cell adhesion by binding cell walls of adjacent cells together.

Primary Cell Wall

Layer formed between the middle lamella and plasma membrane in growing plant cells.
Primarily composed of cellulose microfibrils, hemicellulose fibers, and pectin polysaccharides.
Provides strength and flexibility needed for cell growth.

Secondary Cell Wall

Layer formed between the primary cell wall and plasma membrane in some plant cells.
Forms after primary cell wall has stopped dividing and growing, and thickens to provide strength and support.
Composed of cellulose, hemicellulose, and sometimes lignin, which strengthens the cell wall and aids in water conductivity in plant vascular tissue cells.

Test your knowledge of the plant cell wall's multi-layered structure, including the middle lamella, primary cell wall, and secondary cell wall. Learn about the role of pectins in cell adhesion and how these layers differ in various plant cells.