Final answer:
The plasma membrane functions as a physical barrier, controls the exchange of ions and molecules, facilitates cell recognition, and plays a part in immune system responses. It operates through both passive and active transport to regulate the movement of substances into and out of the cell.
Step-by-step explanation:
The functions of the plasma membrane include serving as a physical barrier, controlling the passage of ions and molecules, facilitating cell recognition, and supporting cellular communication. The correct option regarding the functions of the plasma membrane is C) A. Physical barrier, ions and molecules, cell recognition, genetic material. The plasma membrane's selective permeability allows certain materials to freely enter or leave the cell, while others require specialized structures for transport. Materials can cross the membrane through passive or active transport mechanisms.
Passive transport allows substances to move along their concentration gradient without energy input, which includes simple diffusion, facilitated diffusion, and osmosis. Active transport, on the other hand, requires energy for substances to move against their concentration gradient. This is often mediated by protein pumps and vesicles. Additionally, the plasma membrane's flexibility permits cell shape changes, critical for cells like red blood cells and white blood cells, as they traverse through capillaries.
The surface markers on the plasma membrane play a significant role in tissue and organ formation during embryonic development and are crucial for the immune system's distinction between self and non-self.