Why Do Animal Viruses Have Envelopes and Phages Rarely Do

question 88

Multiple Choice

Why do animal viruses have envelopes and phages rarely do?

• A) Since bacteria don't have cell membranes, the bacterial viruses (phages) don't pick them up when they leave the target cells.
• B) Phages acquire an outer surrounding that is a part of the cell wall of the bacterium they were created in, rather than an outer surrounding of plasma membrane.
• C) Animal viruses will often use the envelope in order to fuse with the plasma membrane of a new target cell, gaining entry into the cytoplasm.
• D) Animal viruses build the envelope inside of the target cell as they are being replicated, but before the cell breaks open and releases them into the extracellular environment. The envelope is a remnant of this building process.
• E) This is a trick question. Plenty of bacteriophages have envelopes that they acquire when they bud through the lipopolysaccharide layer of the bacterial host.

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Definitions:

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