Assembly of enveloped viruses requires (membrane/matrix/receptor) to bring together the nucleocapsid and the envelope.
To determine which component is required for the assembly of enveloped viruses, we can break down each option individually:
1. Membrane: The membrane is an essential part of enveloped viruses. However, it primarily serves as the outer protective layer of the virus rather than being directly involved in the assembly process.
2. Matrix: The matrix is a structural protein found underneath the viral membrane. It plays a crucial role in the assembly of enveloped viruses by helping to bind the nucleocapsid (the genomic material surrounded by a protein coat) to the inner surface of the membrane.
3. Receptor: Receptors are molecules present on the surface of host cells that the virus can specifically interact with to gain entry. While interactions with receptors are crucial for infecting host cells, they are not directly involved in the assembly of the virus.
Therefore, the correct answer is "matrix." The matrix component is required to bring together the nucleocapsid and the envelope during the assembly of enveloped viruses.