Which of the following is NOT a function of the plasma membrane?

The plasma membrane primarily functions as a barrier that protects the cellular contents from the external environment. It plays a crucial role in maintaining homeostasis by controlling the entry and exit of substances through selective permeability, which is vital for regulating the internal environment of the cell.

The facilitation of cell communication is another important function of the plasma membrane. It contains receptor proteins that allow cells to interact with each other and respond to external signals, thus playing a key role in processes such as signaling and recognition.

While the plasma membrane is essential for many processes that maintain cellular health and function, it does not directly produce energy. Energy production occurs mainly in the mitochondria through cellular respiration, where substrates are converted into usable energy (ATP). Thus, the plasma membrane itself is not involved in energy production, making that option the one that does not align with the primary functions of the plasma membrane.