Plasma Membrane: Structure and Function

Running head: APPLIED BIOSCIENCE 365
Assessment 2- Part A
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1APPLIED BIOSCIENCE 365
The plasma membrane defines boundary of a cell and separates it into two primary fluid
compartments namely, intracellular fluid inside cells and extracellular fluid outside cells. It is
made up of lipid bilayer that forms the basic structure of the membrane, and is largely composed
of phospholipids, with traces of cholesterol, glycolipids, and lipid rafts. A phospholipid
molecule contains a hydrophilic phosphate group/head on one end, and hydrophobic chains of
fatty acids that make up the tails. The lipid tails are composed of saturated or unsaturated fatty
acids. Owing to the fact that the phospholipids contain both hydrophilic and hydrophobic
regions, the lipid bilayer is termed as amphipathic (Ingólfsson et al., 2014). However, most often
it gets interrupted by several proteins. Two proteins commonly related to the plasma membrane
are namely, integral/intrinsic or extrinsic/peripheral proteins. The integral proteins are found to
remain embedded in the plasma membrane. Peripheral proteins are located on the outer or inner
surface of the bilayer. However, they are also found attached to the surfaces of the integral
proteins.
Figure 1- Plasma membrane structure
Source- (Nicolson, 2014)