Question

The cell walls of bacteria, fungi, and plant cells, and the extracellular matrix of animal cells are all external to the plasma membrane. Which of the following characteristics are common to all of these extracellular structures?

They are composed of a mixture of lipids and nucleotides.

They must provide a rigid structure that maintains an appropriate ratio of cell surface area to volume.

They must block water and small molecules to regulate the exchange of matter and energy with their environment.

They are constructed of materials that are exported from inside the cell and then transported out of the cell for assemb

Answer 1

The correct option is:

D) They are constructed of materials that are exported from inside the cell and then transported out of the cell for assembly.

The extracellular structures are mainly composed of proteoglycans, complex polysaccharides, water, minerals, and fibrous proteins. These compounds, which are synthesized at various sites inside the cells are transported outside using a mechanism called ‘the constitutive pathway of exocytosis’. They are transported with the help of vesicles to the cell membrane along microtubules of the cytoskeleton. Then, the vesicle membrane fuses with the cell membrane and the contents of the vesicle are secreted out through the fusion pore.