Which is NOT a function of a plasma membrane?
The replication of DNA is not a function of a plasma membrane.
The plasma membrane is a crucial component of cells and performs several essential functions. However, one function that is NOT associated with the plasma membrane is protein synthesis. Protein synthesis occurs in ribosomes, which can be attached to the endoplasmic reticulum or free in the cytoplasm, but it is not a direct function of the plasma membrane. The primary functions of the plasma membrane include:
1. Selective permeability: The plasma membrane controls the entry and exit of substances into and out of the cell. It allows certain molecules to pass through by different mechanisms such as diffusion, facilitated diffusion, and active transport.
2. Cell signaling: The plasma membrane contains receptor proteins that receive external signals and initiate cellular responses. These signals can be chemical messengers such as hormones, neurotransmitters, or growth factors.
3. Cell adhesion: The plasma membrane contains proteins that allow cells to adhere to neighboring cells or extracellular matrix, forming tissues, and maintaining the structural integrity of multicellular organisms.
4. Cell communication: Gap junctions in the plasma membrane allow direct communication between adjacent cells by enabling the exchange of ions and small molecules.
5. Membrane transport: The plasma membrane contains specific transport proteins that facilitate the movement of ions, molecules, and nutrients across the membrane.
6. Maintenance of cell shape: The plasma membrane, along with the cytoskeleton, helps maintain the shape of the cell and provides mechanical support.
In summary, protein synthesis is not a direct function of the plasma membrane.