Final answer:
The viral glycoprotein in an HIV-infected cell binds to host cell receptors, specifically the CD4 receptor on the surface of T cells.
Step-by-step explanation:
In an HIV-infected cell producing HIV virus particles, the viral glycoprotein binds to host cell receptors. This is the first step in the process of infecting the host cell. The glycoprotein, called gp120, specifically binds to the CD4 receptor on the surface of T cells. This interaction allows the virus to enter the cell and initiate the process of viral replication.