Chapter 10 HW

Lyctic Bacteriophage Replication: Release (5)

In this stage of replication, the mature virions exit the cell and lysis occurs.

Lyctic Bacteriophage Replication: Assembly (4)

In this stage of replication, the phage is put together in the host cell. The capsid heads are made from capsomeres, the tails assemble and attach to heads, the tail fibers attach to tails, and this creates a mature virion.

Lyctic Bacteriophage Replication: Attachment (1)

In this stage of replication, the virion comes in contact with the bacterium and the tailfibers bind to the receptors on the surface on the bacterium cell wall.

Lyctic Bacteriophage Replication: Entry (2)

In this stage of replication, the virion overcomes the cell wall barrier and cytoplasmic membrane and injects its genetic material into the bacterium cell.

Lyctic Bacteriophage Replication: Synthesis (3)

In this stage of replication, the virus 19 enzymes cause the bacterium to synthesize viral molecules instead of its own molecules. The steps involved in this stage can very in complexity depending on what type of genetic material is housed in the viral capsid.

The combination of a virus's protein coat and nucleic acid core is called the (capsid/virion/nucleocapsid).

nucleocaspid

Seven (orders/families/classes) represent the highest level of taxonomic rank used in classifying viruses.

orders

In which stage is the viral DNA introduced into the cell? Attachment Penetration Biosynthesis Release Assembly

penetration

_______ is another name for lysogenic phages that have a lysogenic replication cycle.

temperate phages

Which of the following is primarily responsible for the shape of a virion? the specific host protein the virus targets the type of nucleic acid the source of the envelope the number of segments of the viral genome the capsid

the capsid

Which of the following statements describes a generalist virus? It infects many kinds of cells in many different hosts. It can have several different types of genomes. It does not cause disease in the organisms it infects. It does not have a particular sequence of events in its life cycle.

It infects many kinds of cells in many different hosts.

Which of the following is CORRECT regarding the viral envelope? It contains only host cell proteins. It contains only viral proteins. It is composed of sterols. It is composed of sterols of viral proteins only. It is composed of cellular phospholipid membrane, cellular and viral proteins.

It is composed of cellular phospholipid membrane, cellular and viral proteins

What is the fate of the prophage during the lysogenic stage? It is degraded by the activity of host defense enzymes. It is copied every time the host DNA replicates. It is released from the cell by lysing the cell. It is packaged into viral proteins and maintained until the host is exposed to an environmental stress.

It is copied every time the host DNA replicates.

An inactive bacteriophage is a ________ that can remain in the host chromosome and render the bacterium resistant to additional infection by other similar viruses.

Prophage

Which of the following virus families has a double-stranded RNA genome? Filoviridae Retroviridae Reoviridae Rhadoviridae Orthomyxoviridae

Reoviridae

What would be the fate of a lytic bacteriophage if the host cell died prior to the assembly stage? The cell could still be revived by the virus. The virus would not be able to infect new hosts. The virus would infect new hosts.

The virus would not be able to infect new hosts.

How are viruses different from eukaryotic cells? They do not contain enzymes. They do not contain protein. They do not contain genetic material. They require a host in order to reproduce.

They require a host in order to reproduce.

What is the function of the structural elements of a virus? To package and protect the viral genome To provide a source of energy for the virus To use all of the cell proteins

To package and protect the viral genome

Members of a virus family have the same type of nucleic acid. True False

True

Most viruses cannot be seen by light microscopy. True False

True

Protozoa are susceptible to viral attack. True False

True

In what ways do viruses differ from other pathogens? Viruses lack genetic material. Viruses lack cytoplasm and organelles. Viruses are composed of protein only. Viruses have no protein structure. Viruses are composed of both protein and lipid.

Viruses lack cytoplasm and organelles.

Lysogenic viral DNA which has integrated into the host genome is referred to as induction. lysogeny. lytic. a prophage.

a prophage

What is a virion? an extracellular virus genome a virus genome inside a cell an empty capsid a virus genome integrated into a host cell genome a single virus particle outside a cell

a single virus particle outside a cell

Lysogeny is associated with all of the following EXCEPT __________. (viral DNA becoming imbedded within host cell's chromosomes) bacteriophages a prophage increasing virulence of host bacterium animal viruses

animal viruses

How are fungal viruses transmitted? by contact in the air like spores as a result of abrasion as a result of fusion of cells or hyphae by insect vectors

as a result of fusion of cells or hyphae

In which stage does formation of mature viruses occur? Attachment Assembly Biosynthesis Release Penetration

assembly

A(n) ________ is a virus that infects bacterial cells. bacteriophage envelope virion nucleocapsid prion

bacteriophage

The outermost layer of a virion fulfills which of the following functions of the virus? replication protection recognition both protection and recognition both recognition and replication

both protection and recognition

Which of the following is an essential component of all viruses? capsid DNA ribosomes envelope

capsid (surrounds nucleic acid)

Viral capsids are composed of subunits called (capsomeres/nucleocapsids/prions).

capsomeres

Which of the following is NOT represented in viral classification schemes? genus family specific epithet class

class

Which of the following infectious particles is most susceptible to damage? bacteriophage enveloped virus prions naked capsid virus both naked capsid viruses and prions

enveloped virus

A lipid membrane is present in which of the following? prions enveloped viruses naked viruses viroids both prions and viroids

enveloped viruses

The ________ of a virion determines the type of cell it enters. glycoproteins matrix proteins lipid molecules shape nucleic acid

glycoproteins

In _______, a phage is excised from the host chromosome via physical or chemical agents that damage the genetic material of the host.

induction

Host specificity of a virus is due to particular genes that it shares with the infected cell. differences in size between the virus and the host cell. the presence of an envelope. the presence or absence of a cell wall on the host cell. interactions between viral and cellular surface molecules.

interactions between viral and cellular surface molecules.

The envelope found in some virus particles differs from the cytoplasmic membrane of cells in that __________. it contains different types of phospholipids than does a cytoplasmic membrane it is not as flexible as a cytoplasmic membrane it does not perform the physiological functions carried out by the cytoplasmic membrane it is not as dense as a cytoplasmic membrane

it does not perform the physiological functions carried out by the cytoplasmic membrane

A "naked" virus lacks (lipid/nucleic acid/protein).

lipid

When a bacteriophage infects hosts' cells and allows them to grow and replicate normally for many generations before lysis, this is considered ______

lysogeny

The genome of influenzavirus is multiple pieces of linear ssRNA. a single circular ssDNA. a single circular ssRNA. multiple pieces of linear dsDNA. a single linear dsRNA

multiple pieces of linear ssRNA.

How is the lytic cycle different from the lysogenic cycle with respect to the infected host cell? The host cell can only divide during the lytic stage. The viral DNA may integrate into the host genome during the lytic stage. The host cell dies during the lytic stage. The host cell is allowed to live during the lytic stage.

The host cell dies during the lytic stage.

The host DNA is usually degraded during which stage? Biosynthesis Attachment Assembly Penetration Release

Biosynthesis

Which of the following events might trigger induction of a temperate bacteriophage? Exposure to UV light Bacterial conjugation Normal cell division of an infected cell An infected cell entering the logarithmic phase of growth

Exposure to UV light

When the phenotype of a bacterium is changed via ________________, harmless bacteria can become pathogenic and are able to produce deadly toxins and proteins.

Lysogenic conversion

Most viral genomes are much smaller than the genomes of the cells they infect. Which of the following CANNOT be inferred from this statement? Viral genomes usually do not encode all of the enzymes or structures necessary for their replication. Most viruses can infect only certain types of cells. Viral genomes can be enclosed in very small capsids. Viral genomes usually contain fewer genes than cellular genomes.

Most viruses can infect only certain types of cells.

Which of the following statements regarding virus taxonomy is true? Viruses are classified on the basis of the taxonomy of their host organisms. Virus classes are based on the domain of the host organism. Virus classes are well established. The species epithet is a latin descriptor of the virion structure. Some virus family names are derived from the name of an important member of the family.

Some virus family names are derived from the name of an important member of the family.

Which of the following is a characteristic by which viruses are classified? size number of chromosomes type of nucleic acid type of host type of life cycle

type of nucleic acid