What component of the nuclear envelope helps manage the mobility of large molecules?

The pore complex is an essential structure of the nuclear envelope that plays a critical role in regulating the transport of molecules between the nucleus and the cytoplasm. It consists of a series of protein structures known as nuclear pore complexes (NPCs) that span the nuclear envelope, which is the double membrane surrounding the nucleus.

These NPCs allow the passage of large molecules such as RNA and proteins while maintaining the selective barrier function of the nucleus. Through a process that involves specific signals, known as nuclear localization signals (NLS), proteins and other molecules can be actively transported into or out of the nucleus. This selective transport is crucial for cellular function, allowing necessary proteins to enter the nucleus for processes such as transcription and allowing RNA to exit the nucleus to be translated in the cytoplasm.

The other options—nuclear lamina, cytoplasm, and plasma membrane—do not directly manage the mobility of large molecules through the nuclear envelope. The nuclear lamina provides structural support to the nucleus but does not facilitate transport. The cytoplasm is the environment surrounding the nucleus where many cellular processes occur but does not play a direct role in nuclear transport. The plasma membrane surrounds the entire cell and regulates the exchange of substances between the cell and its external environment, which is distinct from