question

Virus morphology does not include which of the following characteristics? A. size? B. shape? C. presence or absence of an envelope? D. host range

answer

D. host range

question

2. Which of the following uses dsRNA as the genome? ?A. parvovirus? B. bunyavirus? C. rotavirus? D. poxvirus

answer

C. rotavirus

question

Which of the following is(are) used in the classification of animal viruses? ?A. virion morphology? B. genome structure?C. genetic relatedness ?D. all of the choices

answer

D. all of the choices

question

The tails of some bacteriophage A. include a contractile sheath.B. rotate like flagella to drive the phage genome into the cytoplasm of the host.C. exhibit oar like motion that drives the phage genome into the cytoplasm of the host.D. none of the choices

answer

A. include a contractile sheath.

question

Late mRNA products in T4 phage include A. phage structural proteins.B. proteins that help with phage assembly without becoming part of the virion.C. proteins involved in cell lysis and phage release.D. all of these

answer

A. phage structural proteins.

question

Viruses infecting algae have never been detected.

answer

FALSE

question

Which of the following represent(s) the way(s) in which enveloped viruses acquire their envelopes? A. Budding through the plasma membrane.B. Budding through internal cellular membranes.C. Viral enzymes are responsible for production of the envelope.D. For some viruses, a is correct; for other viruses, b is correct.

answer

D. For some viruses, a is correct; for other viruses, b is correct.

question

Unlike most enveloped viruses, herpes viruses involve the host __________ membrane in the formation of their envelope. A. plasma? B. nuclear ?C. mitochondrial? D. none of these

answer

B. nuclear

question

The most common type of molecule found on the surface of animal viruses for interacting with host cell receptors is a(n) ?A. lipoprotein.? B. glycoprotein. ?C. phosphoprotein.? D. teichoic acid.

answer

B. glycoprotein.

question

Which of the following does not use RNA as the genome? ?A. poxvirus? B. poliovirus? C. influenza virus ?D. rabies virus

answer

A. poxvirus

question

The largest viruses known are the A. herpesviruses.? B. hepadnaviruses.? C. adenoviruses.?D. mimiviruses.

answer

D. mimiviruses.

question

A __________ infection is one in which the virus quits reproducing and remains dormant for a period before becoming active again. A. persistent ?B. latent? C. slow virus? D. none of these

answer

B. latent

question

In which of the following stages of the viral infectious cycle do enveloped viruses usually acquire their envelopes? ?A. penetrationB. component biosynthesisC. assemblyD. release

answer

D. release

question

For which of the following DNA viruses do(es) DNA replication occur in the cytoplasm rather than in the nucleus? ?A. poxvirusesB. herpesvirusesC. adenovirusesD. DNA replication occurs in the nucleus for all of these.

answer

A. poxviruses

question

A bacterium carrying a dormant phage inserted in the chromosome is called a __________.

answer

lysogen

question

Bacteriophage T4 blocks transcription of host genes using an enzyme that transfers an ______ from NAD onto the alpha subunit of RNA polymerase.

answer

ADP

question

_________ is an unusual base found in the DNA of T-even phages.

answer

Hydroxymethylcytosine

question

_______ mRNA is synthesized before replication of the viral nucleic acid.

answer

Early

question

For most T-even phages, the nucleic acid enters the host cell but the capsid is left outside.

answer

TRUE

question

Glucosylation of hydroxymethylcytosine residues protects phage T4 DNA from cleavage by bacterial restriction enzymes.

answer

TRUE

question

Once a virus establishes lysogeny, it may not switch to the lytic cycle at some later time.

answer

FALSE

question

In the case of phage lambda, termination of lysogeny and entry into the lytic cycle usually occurs in response to environmental damage to the host DNA.

answer

TRUE

question

In viral infections involving double-stranded DNA viruses, all of the viral genes are usually expressed prior to the replication of viral nucleic acid.

answer

FALSE

question

Lysogeny always requires integration of the viral genome into the host chromosome.

answer

FALSE

question

Phage T4 gains release from the infected host cell like many other double stranded DNA phages by interfering with the activity of enzymes that synthesize peptidoglycan.

answer

FALSE

question

Phage T4 protects its DNA from cleavage by host restriction enzymes by A. inactivating restriction enzymes.?B. substituting glucosylated hydroxymethylcytosine for cytosine.?C. methylating bases.?D. replicating very rapidly.

answer

B. substituting glucosylated hydroxymethylcytosine for cytosine.

question

Release of T4 phage from host cells after assembly A. occurs by extrusion and does not result in cell lysis.?B. depends on a protein that interacts with MurA and interferes with normal peptidoglycan synthesis.
?C. requires holin protein which allows the T4 lysozyme to attack the peptidoglycan.
?D. occurs by exocytosis.

answer

C. requires holin protein which allows the T4 lysozyme to attack the peptidoglycan.

question

Bacteriophage that only exhibit lytic replication cycles are called __________ phages. A. temperate? B. virulent? C. intemperate? D. lytigate

answer

B. virulent

question

All bacteriophages infecting members of the Archaea possess genomes made of ?A. dsDNA.? B. ssDNA.? C. dsRNA.? D. ssRNA.

answer

A. dsDNA.

question

A _________________ is a sequence-specific recognition protein with endonuclease activity.
?A. DNA Helicase ?B. terminal transferase? C. restriction endonuclease? D. DNA ligase

answer

C. restriction

question

The protein required for the establishment and maintenance of lysogeny in cells infected with the temperate bacteriophage lambda is the A. lac repressor.B. lambda repressor.C. lambda cos.D. lambda Xis and Int proteins.

answer

B. lambda repressor.

question

The sequence of genes in each T4 virus within a population is the same but starts with a different gene at the 5' end. If each of these linear pieces is circularized, the gene sequences would be identical. The T4 DNA, therefore, is described as being ?A. two fold rotationally symmetrical.B. a linear repeat.? C. circularly permuted. ?D. linearly palindromic.

answer

C. circularly permuted.

question

In T-even phages, which of the following makes the initial contact with the appropriate receptor site? A. tail fiber? B. base plate ?C. collar? D. tail tube

answer

A. tail fiber

question

The latent form of a bacteriophage genome that exists when a phage establishes lysogeny is called a A. lysogen.? B. prophage. ?C. viroid.? D. prion.

answer

B. prophage.

question

Entry of a virus into the lytic cycle after lysogeny has been established is called A. lysogenic conversion.? B. lysogenic reversion.? C. induction.?D. none of the choices

answer

C. induction.

question

Establishment of lysogeny by phage is usually influenced strongly by A. the previous host infected by the virus.
?B. components of the host replication machinery.C. the physiological condition of the host at the time of infection.D. none of the choices

answer

C. the physiological condition of the host at the time of infection.

question

A bacteriophage that can integrate its genome into the host chromosome and not cause lysis of the host cell is said to be ?A. virulent.? B. avirulent.? C. moderate.? D. temperate.

answer

D. temperate.

question

When a viral genome is integrated into the host chromosome but does not result in the lysis of the host cell, the condition is referred to as A. temperate infection.? B. a virulent infectio.? C. lysogeny.? D. a lytic infection.

answer

C. lysogeny.

question

The cascade of events determining whether bacteriophage lambda elects to purpose lysogeny or a lytic cycle begins with a race between the production of the lambda repressor and ?A. integrase.B. N protein.C. endolysin.D. Cro protein.

answer

D. Cro protein.

question

_____________ are able to degrade infecting bacteriophage DNA, thus protecting the host cell. A. Lysozyme? B. Protection exonucleases? C. Restriction endonucleases? D. Modification methylases

answer

C. Restriction endonucleases

question

Attachment of a bacteriophage to its host requires A. specific surface proteins on the bacteriophage.
?B. specific receptor molecules on the host cell.C. nucleic acid protein interactions.D. specific surface proteins on the bacteriophage and specific receptor molecules on the host cell.

answer

specific surface proteins on the bacteriophage and specific receptor molecules on the host cell.

question

In order for bacteriophage to be released from the host by a lysis mechanism, enzymes are required that A. halt ATP synthesis.B. stabilize the cytoplasmic membrane and cell wall.?C. damage the cell wall and cytoplasmic membrane.?D. degrade the host chromosome.

answer

C. damage the cell wall and cytoplasmic membrane.

question

Which of the following is not a function of the replicative form (dsDNA) of phage phiX174?
?A. Direct the synthesis of more RF copies.B. Direct the synthesis of minus-stranded DNA.C. Direct the synthesis of plus-stranded DNA.
?D. Direct the synthesis of mRNA.

answer

B. Direct the synthesis of minus-stranded DNA.

question

The genomes of phiX174 and fd are A. double stranded DNA.B. single stranded DNA.C. double stranded RNA.D. single stranded RNA.

answer

B. single stranded DNA.

question

Parvoviruses are among the simplest known DNA viruses of animals.

answer

TRUE

question

Which of the following uses ssDNA as the genome? ?A. parvovirus? B. poliovirus? C. herpesvirus ?D. poxvirus

answer

A. parvovirus

question

Because their host cells have dsDNA genomes, viruses with RNA genomes cannot rely on host cell enzymes for genome replication or mRNA synthesis.

answer

TRUE

question

A group of viruses that cause severe diarrhea, resulting in over 600,000 deaths worldwide annually is the A. polioviruses.? B. rotaviruses.? C. poxviruses.?D. herpesviruses.

answer

B. rotaviruses.

question

When a _________ enters a host cell, it loses the outermost protein layer and is then referred to by virologists as a double-layered particle (DLP).

answer

rotavirus

question

For bacteriophage with +ssRNA as their genome, which type of nucleic acid is used as the template for the production of more genomic RNA? ?A. -ssRNAB. dsRNAC. -ssDNAD. dsDNA

answer

B. dsRNA

question

Tobacco mosaic virus can be transmitted between individual plants by biting insects.

answer

TRUE

question

One way in which small viruses package more information into a very small genome is to use overlapping genes so that the same base sequence is read in more than one reading frame.

answer

TRUE

question

Almost all known plant viruses are RNA viruses.

answer

TRUE

question

Although poliovirus capsids contain several distinct proteins, these are synthesized as a single polypeptide then cleaved by proteases to produce the individual proteins.

answer

TRUE

question

The genomes of _____________________ cannot function as mRNA and therefore these viruses must bring at least one RNA-dependent RNA polymerase into the host cell during entry. ?A. positive-strand RNA virusesB. double-stranded DNA virusesC. negative-strand RNA virusesD. single-stranded DNA viruses

answer

C. negative-strand RNA viruses

question

Retroviruses have a +ssRNA as their genome. In order to complete an infection, they must first make a __________ molecule, which they use to direct the synthesis of mRNA. ?A. dsRNA? B. dsDNA? C. DNA:RNA hybrid? D. -ssRNA

answer

B. dsDNA

question

Which of the following must bring in a virion-associated RNA replicase when it infects host cells? A. +ssRNA virusesB. -ssRNA virusesC. +dsRNA virusesD. all of the choices

answer

B. -ssRNA viruses

question

The enzyme used by retroviruses to make a DNA copy of their RNA genome is called A. RNA polymerase.? B. DNA polymerase.? C. RNA replicase.?D. reverse transcriptase.

answer

D. reverse transcriptase.

question

Hepatitis B virus is an example of a DNA virus that uses reverse transcriptase in its replication cycle.

answer

TRUE

question

The HBV genome is a circular dsDNA molecule that consists of A. one complete but nicked strand.
?B. segmented DNA.C. a complementary strand.D. one complete but nicked strand and a complementary strand.

answer

D. one complete but nicked strand and a complementary strand.

Microbiology ch27 – Flashcards

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