The cell wall is an envelope found outside the plasma membrane of a plant cell. It appears early in cell development. There are few examples of species that do not have this structure. gymnosperms, for example.
→ What constitutes the cell wall?
The cell wall is basically formed by cellulose, an example of polysaccharide. Cellulose, however, is not the only component, being found also proteins, lipids, enzymes, silica, among other substances.
→ What is the function of the cell wall?
The cell wall has several functions, but undoubtedly the best known is protection and rigidity of the cell. However, the cell wall does not only have this function, it also prevents the cell from breaking down when a lot of water is absorbed, it controls growth, stores some compounds and even acts in defense of vegetable.
→ Primary and secondary cell wall
In plant cells, there are two types of cell wall: the primary and the secondary wall. The latter may or may not be present in a cell, and its presence usually causes the unit to die.
THE primary wall it has a large amount of water and many polysaccharides and proteins. This wall is usually deposited homogeneously, but some regions are thicker than others. The places where there is less deposition of primary components are called point fields.
At secondary wall, there is less water than the primary wall and cellulose is the major component. Sometimes it is also possible to find lignin, a molecule that makes the cell rigid. Unlike the primary wall, the secondary wall can be discontinuous. Normally, in the place where there is a dot field, the secondary wall is not deposited, resulting in the points.
Curiosity: Did you know that, in addition to vegetables, other organisms have an outer shell to the plasma membrane? Fungi, some protists and bacteria are examples of organisms that have this structure. It is noteworthy, however, that the composition of the wall, in these cases, is different.
