Virus Structure and Classification (2B) Practice Test

An experiment aims to classify Virus BB as enveloped vs non-enveloped. Researchers treat virions with either (i) detergent, (ii) protease, or (iii) RNase, then measure infectivity. Detergent reduces infectivity by 10,000-fold; protease reduces infectivity by 100-fold; RNase has no effect unless detergent is applied first. Which classification best fits the virus described?

A lab compares two viruses that bind the same cell-surface receptor. Virus A loses infectivity after exposure to ether, while Virus B retains infectivity. Electron microscopy shows Virus A has a surrounding membrane-like layer with surface spikes; Virus B shows only a protein shell. In a plaque assay, Virus A forms plaques only when cells are not pretreated with a lysosomotropic agent that raises endosomal pH; Virus B plaques are unaffected. Based on the passage, how does the structure influence pathogenicity?