16.E: Acellular Pathogens (Exercises)
16.1: Viroids, Virusoids, and Prions
Other acellular agents such as viroids, virusoids, and prions also cause diseases. Viroids consist of small, naked ssRNAs that cause diseases in plants. Virusoids are ssRNAs that require other helper viruses to establish an infection. Prions are proteinaceous infectious particles that cause transmissible spongiform encephalopathies. Prions are extremely resistant to chemicals, heat, and radiation.
Multiple Choice
Which of these infectious agents do not have nucleic acid?
- viroids
- viruses
- bacteria
- prions
- Answer
-
D
Which of the following is true of prions?
- They can be inactivated by boiling at 100 °C.
- They contain a capsid.
- They are a rogue form of protein, PrP.
- They can be reliably inactivated by an autoclave.
- Answer
-
C
Fill in the Blank
Both viroids and virusoids have a(n) _________ genome, but virusoids require a(n) _________ to reproduce.
- Answer
-
RNA, helper virus
Short Answer
Describe the disease symptoms observed in animals infected with prions.
Critical Thinking
Does a prion replicate? Explain.