Chapter 13:Viruses, Viroids, and Prions

These flashcards cover key concepts and facts from the lecture on viruses, viroids, and prions, including definitions, classifications, and mechanisms of action.

What defines a virus?

A virus is defined as genetic information (either DNA or RNA) enclosed in a protein coat.

What does the term 'virus' mean?

The term 'virus' means 'poison'.

What are obligate intracellular parasites?

Obligate intracellular parasites are viruses that require a living host cell to replicate.

How do viruses affect the host cell's activities?

Inside a host cell, viruses hijack the cell's machinery to direct its activities.

What is a bacteriophage?

A bacteriophage is a virus that infects bacteria.

What are the basic shapes of viruses?

Viruses can be icosahedral, helical, or complex in shape.

Describe the structure of a virion.

A virion consists of nucleic acid surrounded by a protein coat called a capsid.

What is the role of spikes on a virus?

Spikes attach to receptor sites on host cells and aid in viral entry.

How are viruses classified?

Viruses are classified based on the type of cell they infect and other features such as genome structure.

What is lysogenic infection?

Lysogenic infection is when a phage integrates its DNA into the host's chromosome, remaining dormant.

What is antigenic drift?

Antigenic drift refers to small mutations in virus genes that can lead to changes in surface proteins.

What is the consequence of lysogeny for a bacterial cell?

Lysogeny can provide immunity to superinfection and may alter the phenotype of the bacterium.

What is phage therapy?

Phage therapy is the use of bacteriophages to target and destroy specific bacterial pathogens.

What allows phages to undergo horizontal gene transfer?

Errors during phage replication contribute to horizontal gene transfer between bacteria.

What are viroids?

Viroids are small, circular RNA molecules that can cause disease in plants.

What are prions?

Prions are infectious agents composed solely of protein, capable of causing neurodegenerative diseases.

What is replication of RNA viruses characterized by?

Replication of RNA viruses often involves the use of RNA-dependent RNA polymerase.

How do oncolytic viruses work?

Oncolytic viruses specifically target and kill cancer cells by replicating within them.

List some consequences of viral infections in host cells.

Consequences can include cell lysis, transformation into tumor cells, or latency of the virus.

What is the role of reverse transcriptase in reverse-transcribing viruses?

Reverse transcriptase synthesizes DNA from an RNA template.

How do antiviral drugs target viruses?

Antiviral drugs can inhibit viral replication by targeting specific viral enzymes.