1. Cell Membrane: Composed of a lipid bilayer, it provides structural integrity and regulates the entry and exit of substances. 2. Proteins: Integral and peripheral proteins serve as receptors, channels, and enzymes. 3. Glycocalyx: A carbohydrate-rich layer involved in cell recognition and protection. 4. Extracellular Matrix (ECM): Provides structural support and regulates cell behavior through biochemical and mechanical signals.
