What is cellulose's main function in plants

Cell wall

Cell walls are the shell that surrounds the cells of bacteria, archaea, plants and fungi. Animal cells do not have cell walls. A cell wall is made up of polymers.

Plant cell walls consist of cellulose fibrils that are bound into a matrix of pectins, hemicelluloses, proteins and, in some cases, lignin.

The cell wall has two important functions: on the one hand, it serves the stability of the cell and keeps it in "shape", it counteracts the osmotic pressure of the cell. On the other hand protects they protect the inner workings of the cell, e.g. from pathogens (viruses, bacteria, fungi, etc.). In order to stay in contact with the other cells anyway, there are small connecting channels in the cell walls, the plasmodesmata. All cells in the symplast are connected to one another via the plasmodesmata and can exchange substances.

The cell wall consists of two partial walls that are separated by the central lamella. With growing (stretching) cells, cell walls are plastically stretchable. This property is lost in differentiated cells. A distinction is therefore made between primary and secondary cell walls. Cell walls are formed by the cytoplasm.

In young cells (primary cell wall) these consist of 90% carbohydrates (cellulose, hemicelluloses and pectin) and approx. 10% proteins. The primary wall is still permeable to water.

The secondary cell wall is only formed when the cell no longer grows. The microfibrils made of cellulose and hemicellulose are aligned parallel to one another and lignins and minerals are stored in the cell wall.