LearnSmart Chapter 13 Microbiology Assignment

This image shows the ___________ stage of the T4 phage lytic cycle.

Genome entry

Which are the two main criteria used in classifying viruses? Geographic distribution Capsid diameter Pathogenic potential Genome structure Host range

Genome structure Host range

Which of the following are the three general shapes pf most viruses? Spherical Diamond Helical Icosahedral Complex

Helical Icosahedral Complex

Which of the following processes are required for production of the virus particles in a host cell? Cleavage of host polypeptides Replication of viral genome Replication of host genome Translation of viral genes Transcription of viral genes

Replication of viral genome Translation of viral genes Transcription of viral genes

(+) strand genome

Serves as mRNA

Malignant

Spreads to nearby tissue

Proto-oncogene

Stimulates cell growth

Which of the following occur during the synthesis stage of the T4 lytic cycle? Synthesis of phage proteins Synthesis of phage DNA Degradation of bacterial DNA Lysis of the host cell Synthesis of phage polysaccharides

Synthesis of phage proteins Synthesis of phage DNA Degradation of bacterial DNA

Latent state

Viral genome remains silent within the cell

Which of the following are non-cellular infectious agents composed of only a single-stranded RNA molecule? Palsmids Virions Transposons Prions Viroids

Viroids

A viral capsid is made up of subunits called __________. amino acids proteins facets nucleocapsids capsomeres

capsomeres

Enveloped viruses can derive their envelopes from _______. certain host organelles the host cytoplasmic membrane the host matrix protein

certain host organelles the host cytoplasmic membrane

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

cytoplasmic membrane

Animal viruses that do not have an envelope can only enter their host cell by __________.

endocytosis

In a lysogenized bacterium, ________ of the prophage results in a lytic infection. excision integration replication repression

excision

(-) strand genome

is the complement to mRNA

In enveloped viruses, sandwiched between the nucleocapsid and the envelope is the ___________. endocapsid matrix protein exoskeleton nucleocapsid exocapsid

matrix protein

Transmissable spongiform encephalopathies are caused by __________. prions satellite viruses viroids fungi bacteria

prions

A __________ is an animal virus genome residing silently in a host cell genome.

provirus

Replicases are _________ polymerases.

RNA-dependent RNA

One of the early proteins expressed in the T4 lytic cycle is an enzyme called a ___________ that degrades the bacterial DNA.

nuclease

Reverse transcriptase is a(n) _________ polymerase. DNA-dependent RNA RNA-dependent DNA RNA-dependent RNA DNA-dependent DNA

RNA-dependent DNA

The term _________ is used to describe the rupture or bursting of a cell.

lysis

The stage of viral multiplication at which budding occurs is __________. penetration absorption synthesis release assembly

release

Some pathogenic bacteria produce toxins that are encoded on prophage DNA, and these are examples of ___________ conversion.

lysogenic

Most animal DNA viruses will replicate within the host cell's ____________.

nucleus

The phage DNA that is latently incorporated into the bacteria host genome is called a _________. bacteriophage lysogenic provirus prophage persistent infection temperate

prophage

How does bacteriophage nucleic acid enter the host cell? Injection Pinocytosis Engulfment Phagocytosis

Injection

Viral genomes can be? either single-stranded or double-stranded single-stranded only double-stranded DNA or single-stranded RNA double-stranded only

either single-stranded or double-stranded

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

The accumulation of mutations in genes that encode viral surface proteins recognized by the immune system results in a type of antigenic variation called __________. antigenic drift antigenic slip evasion antigenic shift

antigenic drift

When two different strains of a segmented virus enter the same cell, reassortment of the gene segments can occur, resulting in ___________. antigenic shift slip evasion antigenic shift

antigenic shift

Which are the two major categories of viral infections? Acute Persistent Latent

Acute Persistent

Which of the following describes the various viral parts coming together to produce virions? Release Penetration Assembly Absorption

Assembly

Replication of temperate phages and lytic phages have which steps in common? Attachment Integration of the viral genome into the host genome Genome entry Assembly Release Biosynthesis of viral components

Attachment Genome entry Assembly Release Biosynthesis of viral components

List the steps of an animal virus infection cycle in the correct order. Assembly Synthesis of viral proteins and replication of the genome Attachment Release Penetration and uncoating

Attachment Penetration and uncoating Synthesis of viral proteins and replication of the genome Assembly Release

Replication of temperate phages and lytic phages have which steps in common?

Attachment Release Biosynthesis of viral components Genome entry Assembly

Which of the following are classified as persistent infections? Chronic infections Acute infections Latent infections Contagious infections Endemic infections

Chronic infections Latent infections

Double-stranded genome

Consists of both a (+) and (-) strand

The replication strategy of viruses can be divided into three general categories: those used by ________. DNA viruses RNA viruses enveloped viruses reverse transcribing viruses

DNA viruses RNA viruses reverse transcribing viruses

Benign

Does not spread to nearby tissue

Which of the following statements about prions are true? Infectious prion proteins have a different shape from normal prion proteins. Normal prion proteins are resistant to destruction by proteases. Both normal and infectious prion proteins are easily destroyed by heat and chemicals. Infectious prion proteins are insoluble and aggregate in brain tissue. Infectious prion proteins can convert normal prion proteins into abnormal form.

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

Tumor suppressor gene

Inhibits cell growth

Which of the following describes a consequence of lysogeny that could result in human disease? Exocytosis Phage cycling Lysogenic conversion Host cell lysis

Lysogenic conversion

Regarding animal viruses, which of the following statements are true? Viruses use their spikes to attach to host cell receptors. The normal function of host membrane receptors is for viral absorption. Some viruses require more than one host receptor for attachment. Blocking a host receptor with a drug would prevent a virus from infecting that cell.

Viruses use their spikes to attach to host cell receptors. Some viruses require more than one host receptor for attachment. Blocking a host receptor with a drug would prevent a virus from infecting that cell.

The molecules that viral spikes attach to on the host cell in order to gain entry are typically ________. glycoproteins lipoproteins transport proteins lipopolysaccharides

glycoproteins

All of the following are required for synthesis of new virus particles in a host cell EXCEPT ________. homologous recombination genome replication RNA synthesis

homologous recombination

Symptoms of acute viral diseases result from ________. lysogenic conversion host immune response host tissue damage

host immune response host tissue damage

Symptoms of acute viral diseases result from ___________. host immune response lysogenic conversion host tissue damage viral budding

host immune response host tissue damage

Viruses that have an RNA genome and use reverse transcriptase to synthesize a DNA copy of that genome are called _______. retroviruses viroids autoviruses reverse viruses

retroviruses

Viral infections that stick out from the viral envelope or capsid and attach to host cell receptors are termed ________.

spikes

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

tumor

After a virus enters a cell, the nucleic acid separates from the protein coat,a process called _________.

uncoating

Before enveloped viruses bud from a host cell, specific viral proteins insert into the host membrane. These proteins become ________. viral envelope virus capsomeres viral spikes matrix proteins

viral spikes

Which of the following describes a consequence of lysogeny that could result in human disease? Phage cycling Host cell lysis Exocytosis Lysogenic conversion

Lysogenic conversion

Which of the following cycles ends with the death (lysis) of the bacterial host cell? Lytic Filamentous Lysogenic Retroviral

Lytic

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

Some viruses trigger ________ as a means of being released. apoptosis lysis plasmolysis hemolysis

apoptosis

The term _______ is used to describe programmed cell death, a process some non-enveloped viruses trigger as a means of release.

apoptosis

The ___________ or maturation stage of the T4 phage lytic cycle is marked by the formation of ne phage particles inside of the host cell.

assembly

Viral proteins that stick out from the viral envelope of capsid and attach to the host cell receptors are termed ___________.

spikes

Phage DNA and proteins are made during the _________ stage of the T4 lytic cycle.

synthesis

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

temperate

Enveloped viruses can derive their envelopes from _________. the environment the host cytoplasmic membrane certain host organelles the host mastrix protein

the host cytoplasmic membrane certain host organelles

T/F: Enveloped and non-enveloped viruses all mature fully in the cytoplasm of the host cell.

False

T/F: Lysogens are more susceptible to reinfection by the same type of phage.

False

T/F: There is no need to classify viruses because the are not living organisms.

False

Identify all of the methods by which an enveloped virus can gain entry into animal cells. Fusion of the viral envelope and the cell membrane Injection of viral nucleic acids across the cell membrane Endocytosis of the virus by the host cell

Fusion of the viral envelope and the cell membrane Endocytosis of the virus by the host cell

The number of phage particles released from a host cell is called a __________ size.

burst

Productive Infection

New viral particles are produced

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

Persistent

Which is most important for attachment of a virus to a host cell? Number of genes carried by the virus Viral specificity for host receptors Viral shape and size

Viral specificity for host receptors

This image shows the __________ stage of the T4 phage lytic cycle.

attachment

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

Consequences of lysogeny include ________. morphological changes lysogenic conversion phage induction and conversion immunity to superinfection

lysogenic conversion immunity to superinfection

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

lytic

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

lytic

To maintain the lysogenic state, a ________ protein prevents expression of the gene required for excision.

repressor

Which of the following directs the incorporation of phage DNA into a bacterial chromosome? Isomerase Polymerase Lysozyme Gyrase Integrase

Integrase

Which of the following directs the incorporation of phage DNA into bacterial chromosome? Gyrase Lysozyme Polymerase Isomerase Integrase

Integrase

The term _______ is used to describe the rupture or bursting of a cell.

lysis