(N/A) $\Rightarrow$ The structure and function of the plasma membrane are closely related. The membrane consists of a lipid bilayer,proteins,and carbohydrates.
$\Rightarrow$ Integral proteins act as channels or carriers for the transport of ions and molecules across the membrane. For example,in active transport,proteins function as carriers to move minerals against the concentration gradient.
$\Rightarrow$ Carbohydrates (oligosaccharides) attached to the membrane surface act as recognition sites for cell-to-cell signaling and identification,preventing the entry of unwanted external substances.
$\Rightarrow$ The amphipathic nature of phospholipids,with polar hydrophilic heads facing the aqueous environment and non-polar hydrophobic tails facing inward,creates a stable barrier that allows for the selective permeability and fluidity of the membrane.