The main functions of a Eukaryotic cell components part 2
Cell wall – can only be seen in plant cells. They provide the protection a cell needs in terms of maintaining the balance between the osmotic pressure of the intracellular fluid and guarding the cell against water penetration. It is also permeable to certain molecules to allow metabolic activities. The wall is made of microfibrillar networks which are placed on gel like matrix of interlinked molecules. The microfibrillar are mostly cellulose which are assembled together with glucose molecules and producing polysaccharide chains. These chains are interconnected by the hydrogen bonds which are known to be the strongest and unbreakable and thus form the structural unit of microfibril. The microfibrils then bind among themselves with the non-cellulose polysaccharide chains and proteins to form the cell wall.
The cell wall is made up mainly by two layers, the primary wall and the secondary wall. The primary wall is thin and elastic and made up for pectin and cellulose. The secondary wall has three layers Outer, middle and inner layers. This secondary layers is made up of the earlier discussed microfibrils. The primary and secondary layers share an equal amount of hemicellulose in between. There is also the middle lamella, made up of pectin, magnesium and calcium providing rigidity for the cell wall.