Answer:
Cell adhesion molecules are involved in the cell to cell identification and interaction. Membrane proteins produce a variety of substances essential for cell function.
Membrane receptor proteins act as a connection between the cell's internal and external environment.
Transport protein have an important role in the maintenance of concentrations of ions.Explanation:
A membrane protein is a protein molecule attached to or associated with the membrane of a cell or an organelle. They may be listed either as linked to the outer or inner membrane parts. Biological membranes are constructed of a phospholipid bilayer and a large number of proteins for the most vital biological functions of the cells. They are glycolipids, phospholipids, peripheral proteins, integral proteins, sterol, glycoproteins etc.
The main membrane proteins are (1) integral membrane proteins which are permanently bound to the lipid bilayer; (2) peripheral membrane proteins that are temporarily associated with lipid bilayer or with integral membrane proteins; (3) lipid-anchored proteins bound to lipid bilayer bound via amino acid residues.
Integral protein has a wide range in functions such as cell-surface interactions, endocytosis and signalling.
Transmembrane proteins (integral polytopic proteins) are permanently attached to the lipid membrane and span across the membrane. Integral monotopic proteins are permanently attached to the lipid membrane from one side and do no span across the membrane.
It is known that structural proteins are linked to microfilaments in the cytoskeleton. They ensure the stability of the cell.
Cell adhesion molecules are involved in the cell to cell identification and interaction. Membrane proteins produce a variety of substances essential for cell function.
Membrane receptor proteins act as a connection between the cell's internal and external environment.
Transport protein have an important role in the maintenance of concentrations of ions.
For example, glycophorin A is a glycoprotein. It is an integral protein in erythrocytes and rich in sialic acid. This protein enables erythrocytes to adhere to other cells or vessel wall.
Porins are beta proteins. They cross a cellular membrane and act as a pore for the molecule diffusion or act as channels for different types of molecules. In this way, they may control the diffusion of molecules such as carbohydrates, ions and amino acids.
