What are the roles played by; phospholipids, cholesterol, proteins and glycoproteins in the cell membrane?
proteins and phospholipids are the structural makeup of the membrane cholesterol acts to hold the the bilayer together glycoproteins act as recognition sites proteins also have other duties like being active sites for absorbtion of needed materials and as channels for transport through the membrane
1) The cell membrane consists primarily of a thin layer of amphipathic phospholipids which spontaneously arrange so that the hydrophobic “tail” regions are shielded from the surrounding polar fluid, causing the more hydrophilic “head” regions to associate with the cytosolic and extracellular faces of the resulting bilayer. This forms a continuous, spherical lipid bilayer. The arrangement of hydrophilic heads and hydrophobic tails of the lipid bilayer prevent polar solutes (e.g. amino acids, nucleic acids, carbohydrates, proteins, and ions) from diffusing across the membrane, but generally allows for the passive diffusion of hydrophobic molecules. This affords the cell the ability to control the movement of these substances via transmembrane protein complexes such as pores and gates. 2)holesterol is an amphipathic molecule, meaning, like phospholipids, it contains a hydrophilic and a hydrophobic portion. Cholesterol’s hydroxyl (OH) group aligns with the phosphate heads of the phospholip
Cholesterol maintains the cell membranes fluidity levels Glycoproteins act as receptor sites for hormones such as neurotransmitters, as antigens so cell is recognised, Cell attachment and intercellular lubrication Phospholipds form the bilayer and allows lipid soluble (non polar) molecules to diffuse straight through it. Proteins act as channel proteins for water soluble (polar) molecules to diffuse though (transport), cell adhesion. and also a receptor site for molecules. We’ve just done this topid last week at AS level…
