Microbiology ch 6

The major steps in the interaction of an animal virus with its host cell are:

adsorption, penetration, synthesis, assembly, release

Viruses are capable of infecting:

all organisms

The most important function for viral spikes is:

attachment of the virus to a specific host cell

A viral envelope is derived from what host cell structure?

cell membrane

The viral envelope of an animal virus is derived from the ____________________of the host cell.

cell membrane

Which of these is not a general pattern of virus morphology?

complex, helical

Which of the following methods cannot be used to study viruses in a laboratory?

cultures in broth or agar media

Virus-induced damage to the host cell that alters the microscopic appearance of the host cell is called _______________________________

cytopathic effects

In general, RNA viruses multiply in the cell_________________, and DNA viruses multiply in the cell_________________.

cytoplasm, nucleus

Prions are a group of highly infectious viruses. (T/F)

false

A viral structure that resembles a hollow rod which forms as the viral nucleic acid is complexed together with the capsomere proteins and is wound into a helix is an icosahedral structure. (T/F)

false, it is a helical capsid

A lysogenic cycle of a bacteriophage always ends with the destruction of the host bacterial cell. (T/F)

false, it is the lytic cycle

The identical protein subunits which make up the viral capsid are called spikes. (T/F)

false, they are called capsomers

The major difference between a naked virus and an enveloped virus is that a naked virus does not contain nucleic acid and an enveloped virus contains nucleic acid.(T/F)

false, they both contain nucleic acid (Enveloped viruses possess an additional covering external to the capsid called an envelope, which is usually a modified piece of the host's cell membrane.)

The suffix '-viridae' indicates that it is a viral _________________.

family

The specific viral structure consisting of a 3-dimensional polyhedron which resembles a hollow sphere with the nucleic acid inside is called a(an)___________________________.

icosahedral virus

Viruses that can persist in the cell and cause recurrent infections are considered:

latent

A prophage is a/an _______________________stage in the cycle of ___________________________.

latent, bacterial viruses

Viruses are measured using what unit of measure?

nanometers

Clear, well-defined patches in cell cultures that indicate sites of virus infection are called ____________________.

plaque

A _______________________is an inserted piece of viral DNA into the host bacterial cell chromosome. The source of the viral DNA is a bacteriophage.

prophage

Prions are__________________which can damage ___________________.

proteins, nerve cells

In the life cycle of an animal virus, during which phase is the viral nucleic acid replicated and the viral proteins made?

synthesis

Which of the following techniques cannot be used to cultivate viruses for study?

the inoculation of blood agar

The viral nucleocapsid consists of:

the viral nucleic acid and the capsid

A virus has either DNA or RNA, not both. (T/F)

true

Viruses must be within living host cells in order to replicate.(T/F)

true

An oncovirus is capable of initiating_______________________

tumor development

Bacteriophages are:

viruses that infect bacteria

Viruses are not considered living things because:

1) they cannot reproduce by themselves 2) they are not cells 3) they lack metabolism