Virology Flashcards

Flashcards for Virology review, covering historical background, virus characteristics and replication. Intended to help students quickly review concepts for an upcoming exam.

What term did Louis Pasteur use to describe any living disease-causing agent?

Virus

Who gave the first clear evidence of viruses in 1892 by observing the tobacco mosaic disease?

Dimitri Ivanowski

Who proposed that tobacco mosaic disease is caused by a contagium vivum fluidum?

Martinus Beijerinck

Who observed that foot and mouth disease of cattle was caused by a filterable virus?

Loeffler and Frosch

Who isolated the tobacco mosaic virus in 1935 and found that it was largely protein?

Wendell Stanley

What are viruses complexes of?

Proteins and nucleic acids

What is the size range of viruses?

20 to 300 nm

What is a virion?

The infectious virus particle, consisting of the nucleic acid genome surrounded by a protein coat.

Do viruses contain both DNA and RNA?

No, they contain either DNA or RNA, but never both.

What is the protein shell that surrounds the virion called?

Capsid

What are the protein subunits that compose the capsid called?

Capsomers

What is the membrane-like structure that encloses the nucleocapsid in some viruses?

Envelope

What are the projections from the viral envelope known as?

Spikes

The nucleocapsids of viruses are constructed according to certain ___ patterns.

Symmetrical

What kind of symmetry does rabies virus have?

Helical symmetry

What shape do viruses with icosahedral symmetry take?

Icosahedron (20 faces, each an equilateral triangle)

What is a bacteriophage?

A virus that multiplies within bacteria.

Who developed the most commonly used system of virus classification?

David Baltimore

According to the Baltimore classification scheme, what is Group I?

Double-stranded DNA (dsDNA) viruses

According to the Baltimore classification scheme, what is Group II?

Single-stranded (+)sense DNA (ssDNA) viruses

According to the Baltimore classification scheme, what is Group III?

Double-stranded RNA (dsRNA) viruses

According to the Baltimore classification scheme, what is Group IV?

Single-stranded (+)sense RNA (ssRNA) viruses with a positive polarity

According to the Baltimore classification scheme, what is Group V?

Single-stranded (-)sense RNA (ssRNA) viruses with a negative polarity

According to the Baltimore classification scheme, what is Group VI?

Single-stranded (+)sense RNA viruses with a DNA intermediate in life-cycle

According to the Baltimore classification scheme, what is Group VII?

Double-stranded DNA viruses with an RNA intermediate

What virus causes smallpox?

Variola virus

What virus causes chickenpox?

Varicella-zoster virus

What virus causes measles?

Rubeola

What does HIV stand for?

Human immunodeficiency virus

How are dengue viruses spread?

Through the bite of an infected Aedes species mosquito

What virus causes Hepatitis B?

Hepatitis B virus (HBV)

What virus identified in 2019 caused a pandemic of respiratory illness?

SARS-CoV-2

What condition may cause many COVID-19 complications?

Cytokine release syndrome or a cytokine storm

What type of virus causes Rotavirus?

Rotavirus

What virus causes herpes?

Herpes simplex virus

What are the two types of herpes simplex virus?

Herpes simplex virus type 1 (HSV-1) and herpes simplex virus type 2 (HSV-2)

What virus causes polio or poliomyelitis?

Poliovirus

What virus causes rabies?

Rabies virus (RABV)

What are the two main types of influenza virus?

Types A and B

How does the Ebola virus spread?

Through direct contact with the blood, body fluids, and tissues of infected animals or people

What family of viruses causes Hanta disease?

Hantaviruses

What is the first step in viral replication?

Attachment

What is the next step after attachment in viral replication?

Penetration

What is the viral replication process called in which the host cell experiences death?

Lytic cycle of reproduction

What are viruses that remain active within their host cells for a long period without replicating called?

Temperate viruses, or proviruses

What are bacteriophages that remain latent within their bacterial host cell called?

Prophages

What is the cycle called when viruses remain active within their host cells for a long period without replicating?

Lysogenic cycle

What enzyme catalyzes the production of DNA from an RNA template in HIV infection?

Reverse transcriptase

What is budding in the context of viral release?

A process where the nucleocapsids move toward the membrane of the host cell, force themselves through that membrane, and take a portion of the cell membrane as an envelope.

What is lysogeny?

The temperate virus exists in a latent form within the host cell and is usually integrated into the chromosome