CH 13 - Microbiology

Infectious agents that have a simpler structure than viruses include _______

both viroids and prions

A person that had chickenpox will be latently infected with VZV (varicella zoster virus). This means that they ________

can have shingles later on if the virus reactivates

Beign

does not spread to nearby tissue

Bacteriophages play a role in two types of transduction: ________ and _________

generalized specialized

Any gene of the donor cell can be transferred to the recipient cell. This statement describes what type(s) of transduction?

generalized transduction only

A _________ tumor is one that can metastasize or spread to nearby tissue

malignant

In terms of susceptibility to soaps, detergents, and disinfectants, enveloped viruses are _________ non-enveloped viruses

more susceptible than

The smallest virus is approximately 10 ______ in diameter

nanometers

Productive infection

new viral particles are produced

Which of the following are non-cellular infectious agents?

viruses viroids prions

Lysogeny is best described as _______

integration of the viral genome into the host chromosome

Enveloped viruses have an outer layer made up of _______

lipid

At minimum, all viruses are composed of

nucleic acids and proteins

Viroids are pathogens of ______

plants only

Malignant

spreads to nearby tissue

Proto-oncogene

stimulates cell growth

A _____ is a single virus particle

virion

Which of the following statements about prions are true?

Infectious prion proteins are insoluble and aggregate in brain tissue Infectious prion proteins have a different shape from normal prion proteins Infectious prion proteins may convert normal prion proteins into an abnormal form

The viral genome is protected from the environment by a protein shell called the ______

capsid

A viral capsid is made up of subunits called ______

capsomeres

Tumors are abnormal growths that results from a malfunction in the regulation of _______

cell growth

Which type of viral infection is characterized by the continuous, low level production of new virus particles by animal host cells?

chronic

Which of the following are classified as persistent infections?

chronic infections latent infections

Typical route of infection for mad cow disease appears to be via _______

consumption of contaminated food

Viral genomes can be _____

either single stranded or double stranded

Viral genomes can be _______

either single stranded or double stranded

The virus that causes COVID-19 is ______ and phages are typically ______

enveloped non-enveloped

True or False: All virus infections can be clearly characterized as either acute or persistent

false

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

During specialized transduction, DNA from another bacterial cell may be integrated into the recipient cell chromosome by ________ recombination

homologous

In specialized transduction, bacterial DNA may be integrated into the host genome by ______

homologous recomination

Tumor suppressor gene

inhibits cell growth

A viral infection in which the viral genome is integrated into an animal host cell chromosome, yet can reactivate to cause a productive infection, is categorized as a(n) __________ infection

latent

Which of the following infections are analogous to lysogenic infections by bacteriophages in that they involve a viral genome that is silent in the host cell?

latent

Which of the following describes a consequence of lysogeny that result in human disease?

lysogenic conversion

_______ is a change in the phenotype of a lysogen as a consequence of the specific prophage it carries

lysogenic conversion

Infection of bacteria by _____ phages always end with the lysis of the host cell

lytic

Naked viruses do not have an outer lipid bilayer. These viruses are called _________ viruses

non enveloped

In latent infections, the virions are ________

only produced during reactivation

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

persistent

Which are the two major categories of viral infections?

persistent acute

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

persistent or chronic

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

prion

Mad cow disease and chronic wasting disease are caused by infectious agents called _______

prions

Mad cow disease and chronic wasting disease are caused by infectious agents called ________

prions

Transmissible spongiform encephalopathies are caused by ______

prions

Transmissible spongiform encephalopathies are caused by _______

prions

In a lysogenic infection, the phage DNA that is incorporated into the bacterial host genome is called a ________

prophage

Control of cell growth and division are controlled by two sets of genes: those that stimulate growth are called __________ and those that inhibit growth are called _____________ genes

proto-oncogenes tumor suppressor

In _________ transduction, only bacterial genes adjacent to the prophage can be transferred

specialized

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

Many animal viruses have proteins called ______ that attach to receptors on host cells

spikes

The viral proteins that stick out from either the lipid bilayer of enveloped viruses or the capsid of non-enveloped viruses, and attach to host cells are ________

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

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

transduction

True or False: It appears that mad cow disease can be transmitted to humans through consumption of infected beef

true

Viroids ______

cause serious plant disease

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

temperate

The capsid of a virus is composed of precisely arranged identical protein subunits called ______

capsomeres

Which suffix represents a viral genus?

-virus

True or False: Normal prion proteins can have the same amino acid sequence as the abnormal form of the protein

True

A generalized infection cycle of an animal viruses can be divided into five steps: 1. _________; 2 ___________ entry, 3. ____________, 4 __________ and 5 _______

attachment genome synthesis assembly release

Following generalized transduction, DNA from the donor cell may be integrated into the recipient cell chromosome by _____ recombination

homologus

The two categories of persistent infections are _________ and ___________

latent chronic

The typical symptoms of cold sores can be caused by _______

latent HSV-1 that has reactivated an initial infection with HSV-1

Which of the following describe a type of relationship that bacteriophages can have with their host?

latent infection where host cell genotype is changed productive lytic infection

A(n) _______ is an animal virus genome that has integrated into the genome of the host cell

provirus

List the steps of an animal virus infection cycle in the correct order

attachment penetration and uncoating synthesis of viral proteins and replication of the genome assembly release

An animal virus genome residing silently in a host cell genome is called a(n) _______A

provirus

HIV infection _______

has features of both acute and persistent infections

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

virulent

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

viroids

________ are the causative agents of transmissible spongiform encephalopathies

Prions

Specialized transduction ________

produces defective phage particles results from errors in excision of the prophage transfers phage DNA and adjacent host genes

Infectious agents that consist entirely of RNA and that infect plants only are called ________

viroids

During the proposed mechanism of prion replication, the infectious prion protein _______ interacts with the normal protein _________ causing it to misfold

PrP^SC, PrP^C

Symptoms of acute viral diseases result from ________

host immune response host tissue damage

Which of the following are caused by viroids?

citrus exocortis disease potato spindle tuber disease cucumber pale fruit disease

Latent state

viral genome remains silent within the cell

A ________ is a single virus particle

virion

Specialized transduction __________

produces defective phage particles results from errors in excision of the prophage transfer phage DNA and adjacent host genes

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

temperate

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

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

lytic

The nucleocapsid is composed of ____

DNA or RNA, and protein

True or False: Lysogens are more susceptible to reinfection by the same type of phage

False

Which of the following statements describes the mechanism by which prions replicate?

PrP^SC interacts with PrP^C, converting it to PrP^SC

Which of the following are diseases caused by prions?

Scapie Bovine spongiform encephalopathy Creutzfeldt-Jakob disease

Which of the following statements about virus nucleic acid is true?

Viruses contain either DNA or RNA

A prion is best described as ______

a proteinaceous infectious agent

Generalized transducing particles contain which of the following?

bacterial genes

The suffix ______ indicates a viral family

-viridae

Phage heads that contain only bacterial DNA are called generalized __________ particles

transducing

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

transduction

Infectious agents that have a simpler structure than viruses include ________

both viroids and prions

Consequences of lysogeny include _______

immunity to superinfection lysogenic conversion

Infectious agents that consist entirely of RNA and that infect plants only are called _______

viroids

The capsid of a virus is composed of precisely arranged identical protein subunits called ________

capsomers or capsomeres

True or False: Normal prion proteins can have the same amino acid sequence as the abnormal form of the protein

true

Which type of infection can be characterized by the sudden onset of symptoms of a relatively short duration?

acute

A capsid is ____

the protein coat that surrounds the viral genome

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

transduction

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

Infections that have a sudden onset of symptoms of relatively short duration are described as _______ infections

acute

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 persistent

The hepatitis B virus sometimes causes an infection that results in a continuous and low-level production of virus particles. This type of infection pattern is specifically described as a(n) _______ viral infection

chronic

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

viroid