Is the function of the cell wall?

Answer 1

The cell wall is a strong layer outside the cell membrane. It provides the cell structure and support. It is fairly porous, allowing chemical materials, such as nutrients and proteins, to pass through. It permits the organism to build and hold its shape. Although they are found in plant cells, bacteria, fungi, and algae, they are not found in animal cells.

A major function of the cell wall is to act as a pressure vessel, preventing over-expansion when water enters the cell. Remember a cell wall is only present in a plant cell and not an animal cell Hayley

(There are different types of cell wall for plants, bacteria, and fungi, which one do you mean? I assume that you are asking about the plant cell wall.)

Firstly, let us know what a cell wall is.

A cell wall is a tough, usually flexible but sometimes fairly rigid layer that surrounds some types of cells. It is located outside the cell membrane and provides these cells with structural support and protection, and also acts as a filtering mechanism. A major function of the cell wall is to act as a pressure vessel, preventing over-expansion when water enters the cell. They are found in plants, bacteria, fungi, algae, and some archaea (a type of organism that is in between prokaryotes (bacteria) and eukaryotes (plants and animals). Animals and protozoa do not have cell walls.

The materials in a cell wall vary between species, and in plants and fungi also differ between cell types and developmental stages. In plants, the strongest component of the complex cell wall is a carbohydrate called cellulose, which is a polymer of glucose. In bacteria, peptidoglycan forms the cell wall. Archaean cell walls have various compositions and may be formed of glycoprotein S-layers, pseudopeptidoglycan, or polysaccharides. Often, other accessory molecules are found anchored to the cell wall.

Secondly, let's look at the different types of cell walls.

The Plant Cell Wall

The function of the plant cell wall:

1. Maintains cell shape.

2. Prevents the rupture of the cell when excess water enters the cell by osmosis.

3. Filters out large molecules but allows smaller proteins and nutrients(< 30 - 60 kDa) to enter.

The plant cell wall is mostly made up of cellulose, a linear polymer made up of several hundred to ten thousand D-glucose molecules chemically joined together. As there is hydrogen bonding in between in the glucose molecules in different strands, this makes the whole cell wall rigid and inflexible. Thus when excess water enters the cell by osmosis, the cell expands and presses on the cell wall. Since the cell wall is inflexible, it exerts a force back on the cell. Think of the cell wall as a wicker basket in which a balloon has been inflated inside so that it exerts pressure on the walls. The basket does not split immediately because it exerts an opposing force to the balloon. It is the same idea for the plant cell wall. The force is called turgor pressure. This is why plants can stay upright even though they do not have a skeleton to support themselves, unlike animals.

(This part is for your own reading or you are talking about other kinds of cell walls.)

The Bacterial Cell Wall

The function of bacteria cell wall:

1. To maintain tensility (strength).

2. Maintains cell shape.

3. Point of anchorage for external structures (e.g. flagella)

4. A target for antibiotics e.g. Penicillin.

5. An antigen (induces immunity of the host.)

The bacterial cell wall is made up of peptidoglycan (peptide: amino acids derivatives, glycan: glucose derivatives). It is made up of sheets of alternating molecules of NAM and NAG (N-acetyl muramic acid and N-acetyl glucosamine respectively.). These sheets cross-link each other by peptide bridges (made up of L-alanine, D-isoGlutamine, and L-lysine and D-alanine amino acids.) attached to the NAM molecule. These tetrapeptide bridges are furthermore linked by a peptide bond (a bond between amino acids). All of these molecules arranged in this formation cause the cell wall to become very rigid. Thus, the bacteria maintain its shape by its cell wall. Substances enter the cell by specialized transmembrane proteins or by passive diffusion.

The Archaean Cell Wall

The Archaean cell wall is similar to the bacterial cell wall except for an extra layer, the S layer. It is a paracrystalline layer made up of alternating protein and glycoprotein. The unique features of Archaean cell wall are that the membranes are only monolayers, thus they are resistant to peeling off in high temperatures/ other extreme conditions. The bonding between the fatty acid and glycerol phosphate in a normal cell wall is an ester bond, but in Archaean cell wall, the bonding is an ether bond, which is stronger and break less easily in high temperatures.

To help protect and support the Cell's bi-lipid layer membrane.

It protects the cell

made of a stiff material called cellulose.It supports the plant cell and gives it a regular shape it holds up the plant.

Its a rigid layer surrounding the plasma membrane of plant cells. It protects the cell and gives it a definite shape. The cell wall is located outside the cell membrane and provides cells with structural support and protection. It also acts as a pressure vessel, preventing over-expansion when water enters the cell. It covers the cell membrane.

it is only in the plant cell that the cell wall seres as a boundary between the outside

environment and inside the cell.

The cell wall is only present in plants cell .It is non-living and allows all sort of substances to enter and leave the cell freely .It gives protection to the cell membrane and also determines its shape .It is made up of cellulose (a type of carbohydrate).During osmosis process, cell wall helps the cell to withstand the pressure .

A cell wall is a tough, usually flexible but sometimes fairly rigid layer that surrounds some types of cells.

It is located outside the cell membrane and provides these cells with structural support and protection, and also acts as a filtering mechanism. A major function of the cell wall is to act as a pressure vessel, preventing over-expansion when water enters the cell.

They are found in plants, bacteria, fungi, algae, and some archaea. Animals and protozoa do not have cell walls.

and in plants and fungi also differ between cell types and developmental stages.

In plants, the strongest component of the complex cell wall is a carbohydrate called cellulose, which is a polymer of glucose. In bacteria, peptidoglycan forms the cell wall.

Archaean cell walls have various compositions and may be formed of glycoprotein S-layers, pseudopeptidoglycan, or polysaccharides.

Fungi possess cell walls made of the glucosamine polymer chitin, and algae typically possess walls made of glycoproteins and polysaccharides.

Unusually, diatoms have a cell wall composed of silicic acid. Often, other accessory molecules are found anchored to the cell wall.

Function

- provides protection from physical injury

- together with vacuole, provides skeletal support

the function of a cell wall is to attract the female cells

it protects and supports the cell.water and other substances pass through the cell wall to the inside of the cell.

to provide structure and support to the cell, silly