Who postulated the idea that there are "living things" smaller than bacteria (that were not able to be filtered out of solution), and proposed the term "virus"?
|B)||D. Ivanovski and M. Beijerinck|
|C)||Friedrich Loeffler and Paul Frosch|
Identify the individual(s) responsible for demonstrating that a disease in tobacco was caused by a virus.
|A)||D. Ivanovski and M. Beijerinck|
|B)||Friedrich Loeffler and Paul Frosch|
Viruses are best viewed by
|A)||phase contrast microscopy.|
The central core of a virus particle consists of
The simplest virus is a(n)
A viral capsid is composed of
Spikes are essential for the
|A)||replicaton of the virus.|
|B)||attachment of viruses to the host cell.|
|C)||formation of binding layers between the envelope and the capsid.|
|D)||protection of the core of the virus.|
Viruses differ from cells in that viruses
|B)||contain DNA or RNA but not both.|
|C)||only reproduce asexually.|
|D)||have more genes.|
Enveloped viruses include
|D)||all of the above|
Viruses completely lack the genes for synthesis of
|B)||proteins in the capsid.|
|C)||lipids in the envelope.|
|D)||nucleic acids in the core.|
The main criteria presently used for grouping viruses does NOT include
|C)||similarities in genetic makeup.|
The term Poxviridae indicates that we are looking at a virus
Identify the proper order of phases in the life cycle of animal viruses:
|A)||adsorption, uncoating, penetration, synthesis, assembly, and release|
|B)||adsorption, penetration, uncoating, synthesis, release, and assembly|
|C)||adsorption, penetration, synthesis, uncoating, assembly and release|
|D)||adsorption, penetration, uncoating, synthesis, assembly, and release|
Some host cells can harbor a virus and not be immediately lysed by the virus. This results in a persistent infection and is known as a(n)
Which of the following is NOT one of the primary purposes of viral cultivation?
|A)||to isolate and identify viruses in clinical specimens|
|B)||to prepare viruses for vaccines|
|C)||to do detailed research on viral structure, multiplication cycles, genetics, and effects on host cells|
|D)||to classify viruses for taxonomic reasons|
The classification/identification system in the text uses this sequence of characteristics to group viruses:
|A)||host organism, capsid type, envelope presence/absence|
|B)||nucleic acid type, envelope presence/absence, double vs. single-stranded nucleic acid|
|C)||nucleic acid type and strandedness, envelope presence/absence, host organism|
|D)||viral size, shape of capsid, host organism|
Living cells are required for culturing viruses because
|A)||viruses are technically nonliving.|
|B)||viruses require host cell genetic machinery to replicate.|
|C)||viruses are obligate intracellular parasites.|
|D)||all of the above.|
One way to detect the growth of a virus in culture is to observe the degeneration and lysis of infected cells in the monolayer of cells. These areas show up as clear, well-defined patches in the cell sheet called
Viruses can cause damage to infected cells, such as physical damage (e.g. lysis), nuclear inclusions, cytoplasmic inclusions, clumping, etc. These are termed
Identify the viral disease from the list below.
The disease bovine spongiform encephalopathy is also known as
|D)||mad cow disease.|
Spongiform encephalopathies are thought to be caused by
A naked virus exits a cell by ________; an enveloped virus exits a cell by ________
|A)||lysis, budding off|
|B)||budding off, lysis|
|C)||lytic cycle, lysogenic cycle|
The largest virus is bigger than the smallest bacterium.
Viruses can be harmless or even beneficial.
Each envelope is constructed from identical subunits called capsomeres.
In penetration by endocytosis, the entire virus is engulfed by the cell and enclosed in a vacuole or vesicle.
Animal viruses can cause acute infections or can persist in host tissues as lytic infections that can reactivate periodically throughout the host's life.
The two major types of viruses are DNA and RNA viruses.
Viruses that alter host genetic material may cause oncogenic effects.
Viral infections are difficult to treat because the drugs that attack viral replication also cause serious side effects in the host.