Final answer:
The nuclear envelope consists of two phospholipid bilayers with nuclear pores controlled by pore complexes, regulating the exchange of substances between the nucleus and cytoplasm. It is structurally supported by the nuclear lamina and intermediate filaments.
Step-by-step explanation:
The nuclear envelope is a critical cellular structure that encapsulates the contents of the nucleus, providing a barrier between the nucleoplasm and the cytoplasm. This envelope consists of two phospholipid bilayers, the inner and outer membranes, which are contiguous with each other. Unique lipids and proteins can be found on the inner and outer surfaces of both membranes.
The nuclear envelope is dotted with nuclear pores, which are complex protein structures that enable the regulated movement of ions, molecules, and RNA. The flow of these substances is crucial for the function and regulation of the nucleus, affecting processes such as gene expression and RNA processing. The pores are lined with pore complexes that act as gatekeepers, controlling what enters and leaves the nucleus.
Moreover, the structure of the nucleus is supported by the nuclear lamina, a network of intermediate filaments located just inside the nuclear envelope membranes. Adjacent to the lamina, a looser mesh of intermediate filaments helps to maintain the nucleus's position within the cell.