MicrobiologyLesson 1 of 4 in the course Acellular Pathogens

Virus Biology: Structure, Replication, Transmission, Classification, and Diagnosis

5 flashcards · 5 quiz questions · 5 match pairs · 5 fill-in sentences · English

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Summary

Viruses are infectious agents with important differences from cellular organisms. This lesson introduces their defining characteristics and the discoveries that helped scientists recognize them.

In 1892, Russian botanist Dmitri Ivanovski investigated tobacco mosaic disease (TMD), which damages tobacco plants. He passed fluid from infected plants through a Chamberland porcelain filter. The filter's pores were small enough to remove bacteria, yet the filtered fluid could still transmit disease to healthy plants. The infectious agent was therefore smaller than the bacteria the filter retained.

All flashcards

What is a virion?
A complete virus particle containing a DNA or RNA genome enclosed by a capsid; some virions also have an envelope.
What is a host range?
The set of host species that a virus can infect.
What is a fomite?
A contaminated object that can transmit an infectious agent.
What is a capsomere?
A protein subunit that assembles with other subunits to form a viral capsid.
What are ICD codes used for in health care?
They classify diseases and conditions for documentation, reimbursement, and health statistics.

Quiz questions

  1. In Ivanovski's 1892 experiment, filtered fluid from tobacco plants with mosaic disease remained infectious after a Chamberland filter retained bacteria. What did this result support?Answer: The infectious agent was smaller than the bacteria retained by the filter.
  2. What criterion does the Baltimore classification system use to group viruses?Answer: Genome type and the pathway used to produce messenger RNA.
  3. What happens to phage DNA during a lysogenic state?Answer: It is integrated into the bacterial chromosome or maintained in the cell without immediately destroying it.
  4. What roles do influenza hemagglutinin (H) and neuraminidase (N) spikes have, respectively?Answer: H helps with attachment, while N assists release of new virions.
  5. For a person not previously vaccinated, what does rabies post-exposure prophylaxis include?Answer: Rabies vaccine and rabies immunoglobulin, given promptly before symptoms begin.

Based on Microbiology by Nina Parker, Mark Schneegurt, Anh-Hue Thi Tu, Philip Lister, Brian M. Forster (OpenStax), licensed CC BY 4.0. Adapted into a summary, flashcards and quizzes.

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