Chapter 13 Micro

A prion is best described as ______. (An infectious agent that consists of protein and no nucleic acid is called a prion)

a proteinaceous infectious agent

When an enveloped virus gains entry to an animal cell by fusion, the virus envelope fuses with the ______.

cytoplasmic membrane

Which types of viruses are released by budding?

enveloped viruses

Viruses are best described as _______.

infectious agents

The stage of viral multiplication at which budding occurs is ______.

release

Attachment of animal viruses to the host cell typically occurs by means of ______.

spikes

A ______ phage can either cause a lytic infection or can incorporate its DNA into the host genome as a prophage.

temperate

Human cells are larger than viruses by which size factor?

thousand

A complete viral particle, which typically consists of nucleic acid surrounded by a protein coat, is called a(n)

virion

Non-cellular infectious agents composed of only a single-stranded RNA molecule?

viroid

Which of the following are non-cellular infectious agents? Viroids Bacteria Prions Fungi Protozoa Viruses

viroids; prions; viruses

Bacteriophages that exit the host cell at the end of an infection by lysing it are called _______ phages.

virulent

_______ phages cause productive infections that do not kill the host cell.

Filamentous, M13, Temperate, or Lysogenic

The process by which a virus is taken up by a host cell as a result of the host cell's cytoplasmic membrane surrounding the virion to form a vesicle is called ______.

endocytosis

In the case of animal viruses, the molecules that viral spikes attach to on the host cell in order to gain entry are typically ______.

glycoproteins

All of the following are required for synthesis of new virus particles in a host cell EXCEPT ______.

homologous recombination

The study of bacteriophages has advanced much faster than investigations on animal viruses in part because ______.

it is easier to grow bacterial cells than animal cells

The smallest virus is approximately 10 ______ in diameter.

nanometers

True or false: There is no need to classify viruses because they are not living organisms.

False

Which of the following phage types cause productive infections that do not kill the host cell?

Filamentous

Infection of bacteria by __________ phages always ends with the lysis of the host cell.

Lytic

Which of the following about classifying viruses is FALSE? It is not as important as classifying organisms since they are not living entities. Viruses can be classified based on different viral characteristics. An online database classifying viruses is kept by the ICTV (International Committee on Taxonomy of Viruses). It provides a useful way to identify and study viruses.

It is not as important as classifying organisms since they are not living entities.

Which of the following describe a type of relationship that bacteriophages can have with their host? Latent infection where the host cell lyses Productive lytic infection Latent infection where host cell genotype is changed

Productive lytic infection; latent infection where host cell genotype is changed

Which of the following statements about viruses are true? Viruses contain both DNA and RNA in one capsid. The viral capsid is composed of protein. The viral capsid is composed of carbohydrates. Viruses contain RNA or DNA but not both.

The viral capsid is composed of protein; Viruses contain RNA or DNA but not both

Describes the various viral parts coming together to produce virions?

assembly

During the _______ or maturation step in viral multiplication, capsids and genetic material are packaged into virions.

assembly

List the steps of an animal virus infection cycle in the correct order. Start with the earliest at the top.

attachment; penetration and uncoating; synthesis of viral proteins and replication of the genome; assembly; release (absorption/attachment; genome entry; synthesis/biosynthesis; release)

Infectious agents that have a simpler structure than viruses include ______.

both viroids and prions

Bacteriophages that can enter into a lytic cycle or a lysogenic cycle are called _______ phages.

temperate

What processes are required for production of virus particles in a host cell?

transcription, translation and replication of viral genes

A _______ is a single virus particle.

virion