Microbiology - Chapter 6 Viruses & Prions

Choose the term that describes a virus that has a membranous outer covering over its capsid.

Enveloped virus

There are many more antiviral drugs available on the market to treat viral infections than the number of antibiotic drugs available to treat bacterial infections today. Group starts

False

Viruses are inactive macromolecules inside of a host cell.

False

Select all of the statements which provide reasons why it is controversial and difficult to assign species names to viruses.

Some scientists argue that viruses are non-organisms and therefore can't be given species names. Viruses are too changeable.

C. diphtheriae produces a toxin that is really encoded by a lytic phage infecting this bacterium.

True

Select all of the facts that support the concept that viruses are nonliving agents.

Viruses are not able to reproduce outside of a host cell. Viruses have DNA or RNA, but not both. Viruses are unable carry out metabolic processes to generate ATP. Viruses do not have a cellular structure

Viral spikes are used for

attachment to host cells

Host cells of viruses include ______.

humans and other animals. plants and fungi. bacteria. protozoa and algae.

Mad cow disease is caused by a noncellular infectious agent called a _____.

prion

Choose the statement that indicates how cytopathic effects are detected.

Examining infected cells with a microscope

Choose the number that best estimates the annual number of human viral infections worldwide.

It is nearly impossible to measure this number accurately.

Select the terms that describe the possible configurations of viral nucleic acids. Check all that apply

Single-stranded DNA Double-stranded DNA - linear Double-stranded DNA-RNA hybrid Double-stranded DNA - circular Single-stranded RNA, positive-sense Single-stranded RNA, negative-sense Double-stranded RNA

Select the three choices that represent the primary purposes of cultivating viruses.

To isolate viruses from clinical specimens To prepare viruses for vaccines To research the biology of viruses

Select the three methods that are used to cultivate viruses.

Use of cell culture techniques Use of animal inoculation Inoculation of eggs that contain embryos

Choose the statement that correctly explains why viruses are referred to as "filterable."

Viruses are able to pass through a filter because of their small size.

Select all of the facts that support the concept that viruses are living.

Viruses can direct life processes within a cell. Viruses have genetic material that determines their traits. Viruses can reproduce provided they have a host cell. Viruses can evolve

The activation of a prophage is called ______.

induction

Select characteristics exhibited by viral capsids. Check all that apply.

Composed entirely of protein May be an icosahedral shape May be helical in shape Protect the viral nucleic acid Composed of subunits called capsomers May bind to the surface of the host cell

During lysogeny, an inactive prophage state occurs when the viral DNA is inserted into the host ______.

DNA

The majority of human viral infections are fatal.

False

Which of the following will not support viral cultivation?

Live lab animals Embryonated bird eggs Primary cell cultures Continous cell cultures

Select all of the terms that can be accurately used to describe a virus.

Obligate intracellular parasite Infectious particle Dead particle

Select the infectious agents that are noncellular.

Prions Satellite viruses Viroids

Viruses are considered filterable because the cell-free portion of filtered infectious fluids could still transmit disease in experiments.

True

Culturing of viruses can occur using ______ methods such as live animal inoculation.

in vivo

A naked virus only has a/an ______.

nucleocapsid

Some strains of human papillomavirus (HPV) can cause cellular changes that lead to the development of cervical cancer. Infections by such oncogenic viruses are known as

transforming infections.