Comprehensive Principles of Virology, Morphology, and Baltimore Classification (copy)

What are hepatitis B virus genomes characterized as?

Partially double-stranded DNA with reverse transcriptase.

What does 'obligate intracellular parasite' mean in the context of viruses?

A virus must rely on a host cell's machinery to replicate.

What significant contribution did Dmitry Ivanovsky make to virology?

He conducted early experiments that led to the discovery of viruses.

What defines positive-sense RNA viruses?

Viral RNA that is immediately functional as messenger RNA upon entering a host cell.

What is the primary role of the capsid in a virus?

To protect and encapsulate the viral genome.

Which virus classification system is based on the structure of viral genomes and mRNA synthesis?

The Baltimore Classification System.

What are capsomeres in relation to a virus?

Protein subunits that come together to form the capsid.

What are the two mandatory components all viruses possess?

Nucleic acid and protein.

How do bacteriophages infect bacterial cells?

By docking onto surface receptors and injecting their DNA into the cytoplasm.

What characteristic distinguishes prions from viruses?

Prions are misfolded proteins lacking nucleic acids.

How do negative-sense RNA viruses function within a host cell?

They must first be transcribed into positive-sense RNA before translation.

What is a viroid?

A naked infectious strand of nucleic acid that lacks any protein coat.

How are the families of viruses named in taxonomy?

They end with the suffix '-viridae'.

What type of RNA do viruses in Class 4 of the Baltimore classification utilize?

Single-stranded positive-sense RNA.

What does the term 'virus' mean etymologically?

Derived from the Latin word for 'poison'.

What is the main clinical significance of the viral enzyme integrase?

It integrates retroviral DNA into the host cell genome.

What does the term 'virion' refer to?

The complete, inert viral particle outside of a host cell.

What is the primary distinction between a virus and the disease it causes?

A virus is the infectious agent, while the disease is the clinical manifestation.

What is unique about the replication cycle of retroviruses?

They replicate through a reverse transcription process where RNA is transcribed into DNA.

Which structural feature allows the polio virus to maintain its infectivity?

Its capsid protects its RNA genome.