Chapter 13

Which of the following terms is used to describe a viral RNa genome which cannot be immediately translated into protein?

(-) strand

Which of the following are late proteins of the T4 lytic cycle?

T4 tail fibers T4 capsomere components

Identify the method by which a non-enveloped virus can gain entry into animal cells

endocytosis of the virus by the host cell

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

excision

In ss (-) RNA viruses, the enzyme replicase is important because:

it uses (-) RNA as a template to make (+) RNA, which can be used for protein synthesis

Which term is used to describe the protein layer that is sandwiched between the capsid and envelope in enveloped viruses? exoskeleton exocapsid endocapsid matrix nucleocapsid

matrix

Before budding, viral proteins are inserted into the host cytoplasmic membrane. These proteins become: virus capsomeres matrix proteins viral spikes viral envelope

viral spikes

Most viral spike proteins bind to protein receptor molecules on the host cell that are classified as ________

glycoprotein

What are the molecules (receptors) that viral spikes attach to on the host cell typically composed of the following?

glycoproteins

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

lysogenic conversion

Consequences of lysogeny include:

lysogenic conversion immunity to superinfection

During the genome entry stage of the T4 lytic cycle, the enzyme T4 ___________ degrades small portions of the bacterial cell wall

lysozyme

In order for ss (-) RNA viruses to synthesize viral proteins, they must first:

make a (+) strand copy of the (-) strand RNA

The protection of lysogens against infection by the same phage is provided by the repressor protein that will bind to the _________ on incoming phage DNA, preventing expression of the phage genes

operator

restriction-modification systems protect bacteria from phage infection by degrading incoming phage DNA using which two types of enzymes?

restriction enzymes modification enzymes

Which of the following are bacterial defenses against phage infection?

restriction modification systems CRISPR system altering receptor sites

____________ phages enter the prophage state, while ________ phages burst the host cell shortly after infection

temperate lytic

True or false: lysogens are more susceptible to reinfection by the same type of phage

false

In double-stranded RNA viruses, the viral replicase uses the ________ strand of RNA to make a ___ strand of RNA that can then be translated

negative postitive

Enveloped viruses acquire their outer covering

from the host cell cytoplasmic membrane

True or false: enveloped and non-enveloped viruses all mature fully in the cytoplasm of the host cell.

true

Which of the following about classifying viruses is FALSE? -viruses can be classified based on different viral characteristics -an online database classifying viruses is kept by the ICVT -It is not as important as classifying organisms since they are not living entities -it provides an easy way to identify and study viruses

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

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

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

Which of the following processes would block phage attachment to a bacterial cell?

-covering of bacterial surface receptors -modifying bacterial surface receptors

During prion replication, the infectious prion protein ______ interacts with the normal protein __________, causing it to misfold

PrPsc PrPc

During the __________ step in viral multiplication, capsids and genetic material are packaged into virions

assembly

The ____________ stage of the T4 lytic cycle is marked by the formation of new phage particles inside of the host cell

assembly

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

assembly

In order to infect an animal cell, viruses must

attach to receptors on the host cytoplasmic membrane

Temperate phage are more likely to enter the lysogenic cycle when:

bacterial cells are growing slowly

Which of the following is NOT a classification of bacteriophage based on the type of infection they product in the host?

complex phage

During generalized transduction, DNa from another bacterial cell is integrated into the recipient cell chromosome by ___________ recombination

homologous

Which of the following describes a type of relationship that bacteriophages can have with their host? productive lytic infection productive infection where host cell does not lyse latent infection where host cell phenotype is changed latent infection where the host cell lyses

productive lytic infection productive infection where host cell does not lyse latent infection where host cell phenotype is changed

Reassortment of gene segments that encode viral surface proteins that are recognized by the immune system can result in a loss of the immune system's ability to recognize and respond to the virus. This phenomenon is called antigenic _________

shift

The late proteins of the T4 lytic cycle include ___________ proteins that make up the phage particle such as tail fibers and capsomers

structural

The M13 phage has a single-stranded DNA genome. Its replicative form (RF) is a double-stranded DNA molecule. Where does the second strand of DNA come from?

synthesized by host DNA polymerase

Which statement about a single strand (+) RNa viruses is true?

the viral genome functions as mRNA and is translated

Which of the following statement about viroids are true?

they can cause significant crop losses they cause serious plant disease

Many lysogenized bacteria produce which of the following which are harmful to people?

toxins

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

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

Which of the following are the first viral proteins produced in the T4 lytic cycle? -T4 structural proteins such as tail fibers and capsomers -nuclease to digest the host DNA -T4 lysozyme to degrade the bacterial cell wall so that the viral genome can be injected -protein to stop the bacterial RNA polymerase from recognizing bacterial promotors

-nuclease to digest the host cell --protein to stop the bacterial RNA polymerase from recognizing bacterial promotors

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

endocytosis

Which of the following are characteristics of specialized transduction? -transfers phage DNA and adjacent host genes -errors occur in excision of prophage -transfers only phage DNA -produces defective phage particles -errors occur in phage head packing

-transfers phage DNA and adjacent host genes -errors occur in excision of prophage -produces defective phage particles

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 virus adsorption -blocking a host receptor with a drug would present a virus from infecting that cell -some viruses require more than one host receptor for attachment

-viruses use their spikes to attach to host cell receptors -blocking a host receptor with a drug would present a virus from infecting that cell -some viruses require more than one host receptor for attachment

The restriction-modification defense system involves restriction ___________ that digest phage DNA at specific nucleotide sequences and enzymatic modification of _________ DNA to prevent in digestion

enzymes host

Reverse transcriptase uses a viral RNA template to synthesize DNA which can then be

integrated into a host cell chromosome where it remains latent transcribed and translated to form new virirons

Which of the following statements about prions are true?

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