AP BIOLOGY

Detailed explanation-1: -The fundamental structure of the membrane is the phospholipid bilayer, which forms a stable barrier between two aqueous compartments.

Detailed explanation-2: -The phospholipid bilayer formed by these interactions makes a good barrier between the interior and exterior of the cell, because water and other polar or charged substances cannot easily cross the hydrophobic core of the membrane.

Detailed explanation-3: -1: The plasma membrane: The plasma membrane is composed of phospholipids and proteins that provide a barrier between the external environment and the cell, regulate the transportation of molecules across the membrane, and communicate with other cells via protein receptors.

Detailed explanation-4: -The plasma membrane is a structure that forms a barrier between the cytoplasm inside the cell and the environment outside the cell. Without the plasma membrane, there would be no cell. The membrane also protects and supports the cell and controls everything that enters and leaves it.

Detailed explanation-5: -Phenolics are thought to contribute to the physical barrier through cross linking to form a hardened wall that cannot be easily degraded by enzymes employed by pathogens (Zeyen et al., 2002).