Question

Describe the function of the cell wall and discuss the structural differences in a gram positive and gram negative cell wall.

Answer 1

The function of the cell wall:

Provide support and plasticity

It can prevent water loss. In addition it can work as a filter.

Provide protection from insects and pathogens

Keep the shape of the plant.

The structural differences in a gram positive and gram negative cell wall:

Gram positive cell walls contain a thick peptidoglycan layer with techoic acids. Cell wall is smooth and 20-30 nm thick, and it contains 70-80% murein and a low lipid content. Porin is absent. Outer membrane is absent. The S-layer is attached to the peptidoglycan layer.

On the other hand, gram negative cell walls contain a thin peptidoglycan layer without techoic acids. Cell wall is wavy and 8-12 nm thick, and it contains 10-20% murein and 20-30% lipid content. Porin occurs in outer membrane. Outer membrane is present. The S-layer is attached directly to the outer membrane.