What is a major role of the proteins contained in the nuclear envelope?

The major role of the proteins contained in the nuclear envelope is to permit the passage of essential ions and molecules. The nuclear envelope is composed of two lipid membranes that encase the nucleus, and it contains nuclear pore complexes made up of proteins. These pore complexes serve as gateways, regulating the transport of various substances, such as RNA and proteins, between the nucleus and the cytoplasm. This selective transport is crucial for processes like gene expression, where mRNA needs to exit the nucleus and ribosomal proteins must enter, thereby maintaining the necessary cellular functions and overall homeostasis.

Other options, while they denote important cellular processes, do not accurately describe the primary function of the proteins in the nuclear envelope. Facilitating respiration pertains more to cellular respiration processes primarily involving mitochondria. Enhancing cell growth relates to various growth factors and signaling pathways rather than a direct function of the nuclear envelope itself. Decomposing waste products pertains more to lysosomal function within the cell and does not fall under the responsibilities of nuclear envelope proteins.