Chapter 13 smartbook

Which of the following about classifying viruses is FALSE?

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

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

both viroids and prions

Which type of viruses are released by budding?

enveloped viruses

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

The smallest virus us approximately 10 ______ in diameter.

nanometer

Which of the following processes are required for production of virus particles in a host cell?

- translation of viral genes - replication of viral genome - transcription of viral genes

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

virulent

The major categories of animal viral infections are ______ infections, characterized by the sudden onset of symptoms of a relatively short duration, and _____ infections that can continue with or without symptoms for years.

acute and persistent

What are the two major categories of viral infections?

acute and persistent

A generalized infection cycle of an animal viruses can be divided into five steps:

attachment, genome entry, synthesis, assembly and release

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

Oncoviruses are viruses that can

cause cancer in humans

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

filamentous

Which form of transduction results from packaging errors during phage assembly?

generalized

_____ transduction is the result of packaging errors during the assembly stage of phage replication.

generalized

Most animal DNA viruses replicate within the host cell's

nucleus

Viruses that can cause cancer in humans are known as ___ viruses

oncogenic

In which type of infection does the virus remain in the host for years, sometimes without symptoms?

persistent

_____ infections remain for years, or even the lifetime of the host, sometimes without any symptoms.

persistent

Which of the following are non-cellular infectious agents?

prions, viroids, viruses

The stage or viral multiplication at which budding occurs is

release

The virally encoded polymerase for replication of RNA viruses is called a

replicase

Which form of transduction results from excision errors during the transition from a lysogenic to lytic cycle?

specialized

_____ transduction is the result of excision errors made as temperate phages transition from a lysogenic to a lytic cycle.

specialized

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

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

temperate

In acute viral infections, although the infected host cells may die, the host may survive because _____.

the host's immune system may gradually eliminate the virus

Human cells are larger than viruses by which size factor?

thousand

Bacteriophages play a fundamental role in a type of horizontal gene transfer called

transduction

What term is used to describe the transfer of genetic information from one bacterium to another bacterium by a bacteriophage?

transduction

An abnormal growth of tissue resulting from a malfunction in the normally highly regulated process of cell growth is a _____

tumor

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

virion

A(n) _____ is an infectious agent that lacks a capsid and consists only of RNA

viroid

Which of the following are non-cellular infectious agents composed of only a single-stranded RNA molecule?

viroids

An infectious agent that consists of protein and no nucleic acid is called a(n)

prion

Tumors are abnormal growths that result from a malfunction in the regulation of ______.

Cell growth

Replicases are ___ polymerases.

RNA-dependent RNA

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

homologous recombination

Symptoms of acute viral diseases result from

host immune response host tissue damage

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

_____ phages 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

In animals, replication of most DNA viruses occurs within the host cell's

nucleus

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

assembly

Which of the following describes the various viral parts coming together to produce virions?

assembly

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

cytoplasmic membrane