The primary cell wall is a cell wall layer found in many living plant cells. It is a thin, semi-firm cell wall found within the middle lamella of the cell.
The primary cell wall is composed of a specifically arranged matrix which forms the popular cell wall. It is always made from pectins, cellulose, and hemicellulose. In the primary cell wall, coils of cellulose hydrogen-bond to one another, forming a cellulose βcableβ or microfibril. These microfibrils overlap with a net of pectins which hydrogen-bond to each other and to the cables and are secured by parallel crosslinks of hemicellulose.
The primary cell wall may also be made from various other materials such as glycoproteins, waterproofing materials, and lignin.
The majority of the primary cell wall is made from hydrophilic substances (pectin and hemicellulose). This allows water to permeate between cells through the primary cell wall. Contrarily, due to the presence of the rigid cellulose microfibrils, the orientation of the microfibrils affects the directional growth and expansion of the plant. This orientation is determined by the cytoskeleton within the cell membrane of the plant cell.