21.  Visible, clear, well-defined patches in a monolayer of virus-infected cells in a culture are called  
A.  lysogeny.
B.  budding.
C.  plaques.
D.  cytopathic effects.
E.  pocks.

22.  Viral growth in bird embryos can cause discrete, opaque spots in the embryonic membranes called  
A.  lysogeny.
B.  budding.
C.  plaques.
D.  cytopathic effects.
E.  pocks.

23.  Viruses that cause infection resulting in alternating periods of activity with symptoms and inactivity without symptoms are called  
A.  latent
B.  oncogenic.
C.  prions.
D.  viroids.
E.  delta agents.

24.  Oncogenic viruses include all the following except   
A.  Hepatitis B virus.
B.  Measles virus.
C.  Papillomavirus.
D.  HTLVI and HTLVII viruses.
E.  Epstein-Barr virus.

25.  Which of the following is a type of cytopathic effect?   
A.  inclusions in the nucleus
B.  multinucleated giant cells
C.  inclusions in the cytoplasm
D.  cells round up
E.  All of the choices are correct.

26.  Uncoating of viral nucleic acid   
A.  does not occur in bacteriophage multiplication.
B.  involves enzymatic destruction of the capsid.
C.  occurs during penetration in the multiplication cycle.
D.  occurs before replication.
E.  All of the choices are correct.

27.  Infectious protein particles are called  
A.  viroids.
B.  phages.
C.  prions.
D.  oncogenic viruses.
E.  spikes.

28.  Infectious naked strands of RNA are called  
A.  viroids.
B.  phages.
C.  prions.
D.  oncogenic viruses.
E.  spikes.

29.  Creutzfeld-Jacob disease is   
A.  caused by a chronic latent virus.
B.  initiated by an oncogenic virus.
C.  caused by a viroid.
D.  a spongiform encephalopathy of humans.
E.  also called “mad cow disease”.

30.  Satellite viruses are  
A.  also called viroids.
B.  dependent on other viruses for replication.
C.  the cause of spongiform encephalopathies.
D.  significant pathogens of plants.
E.  All of the choices are correct.