Which function is not performed by the plasma membrane in cells?

The plasma membrane plays several essential roles in the life of a cell, including selective permeability, which allows certain substances to enter or exit the cell while restricting others. This selective barrier is crucial for maintaining homeostasis and regulating the internal environment of the cell.

Cell signaling is another important function of the plasma membrane. It contains various receptors that allow the cell to receive and respond to external signals, such as hormones or nutrients. This communication is vital for coordinating cellular activities and responses to changes in the environment.

Energy production and protein synthesis, however, take place within different cellular structures. Energy production primarily occurs in the mitochondria, where ATP is generated through processes such as cellular respiration. Protein synthesis takes place at ribosomes, which may be free in the cytoplasm or attached to the endoplasmic reticulum, facilitating the creation of proteins based on genetic instructions.

Consequently, the function that is not associated with the plasma membrane is the synthesis of proteins, as this occurs elsewhere in the cell.