Which components primarily make up the plasma membrane?

The plasma membrane is fundamentally composed of a bilayer of phospholipids, which are a type of lipid, and this structure is crucial for its role as a barrier that separates the interior of the cell from the external environment. The hydrophobic (non-polar) tails of the phospholipids are oriented inward, away from the aqueous environment, while the hydrophilic (polar) heads face outward. This arrangement creates a semi-permeable membrane that regulates the movement of substances in and out of the cell.

In addition to lipids, integral and peripheral proteins are embedded within and associated with the membrane, serving various functions such as transport, signaling, and structural support. The presence of non-polar proteins, which can integrate into the lipid bilayer, contributes to the fluidity and function of the membrane. This combination of lipids and proteins allows the plasma membrane to maintain its integrity while also playing a vital role in cellular communication and transport.

The other options do not accurately capture the primary composition of the plasma membrane. For instance, DNA and RNA are nucleic acids involved in genetic information storage and transmission, not structural components of the membrane. Proteins and carbohydrates are present in the membrane, but they do not provide the primary structural