Describe the process by which a virus enters a cell.

“Naked” viruses penetrate the cell by endocytosis – immersion of the cell membrane at the site of their adsorption. Otherwise, this process is known as viropexis [virus + Greek. pexis, attachment]. Dressed viruses enter the cell by fusing a supercapsid with a cell membrane with the participation of specific F-proteins (fusion proteins). Acidic pH values ​​facilitate the fusion of the viral membrane and cell membrane. With the penetration of naked viruses into the cell, vacuoles (endosomes) are formed. After the penetration of “dressed” viruses into the cytoplasm, partial deproteinization of the virions and modification of their nucleoprotein (undressing) occurs. Modified particles lose their infectious properties; in some cases, their sensitivity to RNase, neutralizing effect of antibodies (AT), and other signs specific to individual virus groups change.