Exam 24: Viruses and Subviral Agents

How are viruses classified by the ICTV?

The nucleic acid core of the virus is not surrounded by a protein coat called a capsid.

Bacteria protect themselves from bacteriophage infections by producing restriction enzymes that cut up foreign RNA of the phage.

Viral proteins can damage host cells by which process?

Bacteriophages attach to the cell walls of bacteria by envelope proteins.

What are subviral agents that depend on co-infection of a host cell with a helper virus?

Briefly describe the nucleic acid core, capsid, and envelope of viruses.

Which of the following is the most common structure of a virus?

Retroviruses have a DNA polymerase called reverse transcriptase, which transcribes the RNA genome into a DNA intermediate.

Before an animal cell's membrane fuses with a virus, the virus must first:

Polydnaviruses are particles that consist of multiple circles of _______________ encased in capsid proteins and an envelope.

Which statement describes a virulent phage?

What is a very small infective agent that consists of a core of nucleic acid and is dependent on a living host?

Which of the following cause disease and often death?:

What is the purpose of phage therapy?

Dr. Stanley Prusiner concluded that the infective agent of CJD was not a virus because it was not sensitive to radiation, which mutates nucleic acids.

Which has an unusual characteristic in that their circular DNA does not have genes for making the proteins needed to replicate and produce new viruses?