Deck 27: Viruses

Question 1

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

Answer 1

ADP ADP-ribose ADP-ribosyl

Question 2

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 2

D

Question 3

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 the above are correct.

Answer 3

D

Question 4

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

Question 5

_____________ is / are able to degrade infecting bacteriophage DNA,thus protecting the host cell.

A)Lysozyme
B)Protection exonucleases
C)Restriction endonucleases
D)Modification methylases

Question 6

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.

Question 7

The tails of some bacteriophage

A)include a tail sheath that shortens.
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 are correct.

Question 8

For most T4 phages,the nucleic acid enters the host cell but the capsid is left outside.

Question 9

Using the ICTV taxonomy system,a virus name ending in "viridae" would be part of which grouping?

A)Order
B)Family
C)Subfamily
D)Genus

Question 10

Due to the diversity of retroviruses,they can be placed into more than one Baltimore system group.

Question 11

If a single stranded RNA virus contains genomic RNA that is identical to the mRNA that it produces,what type of virus is this categorized as?

A)Plus Strand
B)Positive Strand
C)Plus Strand or Positive Strand is acceptable.
D)Minus Strand
E)Negative Strand

Question 12

A _____________ is a sequence-specific recognition protein with endonuclease activity.

A)DNA helicase
B)terminal transferase
C)restriction endonuclease
D)DNA ligase

Question 13

In T4 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

Question 14

If a single stranded RNA virus contains genomic RNA that is complementary to the mRNA that it produces,what type of virus is this categorized as?

A)Plus Strand
B)Positive Strand
C)Minus Strand or Negative Strand is acceptable.
D)Minus Strand
E)Negative Strand

Question 15

Bacteriophage that only exhibit lytic replication cycles are called __________ phages.

A)temperate
B)virulent
C)intemperate
D)lytigate

Question 16

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.

Question 17

Rubulavirus falls under which group of the ICTV nomenclature system?

A)Order
B)Family
C)Subfamily
D)Genus

Question 18

__________ is an unusual base found in the DNA of T4 phages.
or

Question 19

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

Question 20

A reverse transcribing DNA virus that wants to replicate its genome must first convert the dsDNA to _______ before using that to create copies of the dsDNA genome.

A)single strand DNA
B)double strand DNA
C)double strand RNA
D)single strand RNA

Question 21

The most common type of molecule found on the surface of animal viruses for interacting with host cell receptors is a _________.

A)lipoprotein
B)glycoprotein
C)phosphoprotein
D)teichoic acid

Question 22

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

Question 23

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

Question 24

Nearly all bacteriophages infecting members of the Archaea possess genomes made of _________.

A)dsDNA
B)ssDNA
C)dsRNA
D)ssRNA

Question 25

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 the choices are correct.

Question 26

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

Question 27

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.

Question 28

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.

Question 29

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)Depending on the virus,budding may be either through the plasma membrane or internal cellular membranes.

Question 30

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 that allows the T4 lysozyme to attack the peptidoglycan.
D)occurs by exocytosis.

Question 31

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.

Question 32

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 are correct.

Question 33

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 are correct.

Question 34

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.

Question 35

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 the choices are correct.

Question 36

Which of the following does not use RNA as the genome?

A)Poxvirus
B)Poliovirus
C)Influenza virus
D)Rabies virus

Question 37

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 infection
C)lysogeny
D)a lytic infection

Question 38

If the bacteriophage lambda enters into a host cell and integrates its genome into the host cell,the phage has entered the __________ cycle.
or

Question 39

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

Question 40

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

Question 41

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

Question 42

Parvoviruses are among the simplest known DNA viruses of animals.

Question 43

Which of the following is not a function of the replicative form (dsDNA)of phage phiX174?

A)Function to direct the synthesis of more RF copies.
B)Function to direct the synthesis of minus-stranded DNA.
C)Function to direct the synthesis of plus-stranded DNA.
D)Function to direct the synthesis of mRNA.

Question 44

The genomes of phiX174 and fd are

A)double stranded DNA.
B)single stranded DNA.
C)double stranded RNA.
D)single stranded RNA.

Question 45

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)-ssRNA
B)dsRNA
C)-ssDNA
D)dsDNA

Question 46

In the CRISPR / Cas system of a particular bacterial cell,it is noted that there are six spacer regions.What does this suggest about the bacterial cell?

A)The cell has been infected by six viruses in the past.
B)The cell has developed protection from six different viruses.
C)The cell has six CAS genes due to past infections by viruses.
D)The cell has been infected by six viruses in the past and now has developed a level of protection against all of them.

Question 47

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).
or

Question 48

When RNA-dependent RNA polymerase is synthesizing mRNA it is functioning as a .

A)replicase
B)ligase
C)helicase
D)transcriptase

Question 49

Viruses infecting algae have never been detected.

Question 50

Which enzyme is used by RNA viruses to directly replicate the viral RNA genome?

A)Reverse Transciptase
B)DNA-dependent RNA polymerase
C)RNA-dependent RNA polymerase
D)RNA-dependent DNA polymerase

Question 51

RNA-dependent RNA polymerases are needed by which group of viruses?

A)Double stranded RNA viruses
B)Plus strand RNA viruses
C)Minus strand RNA Viruses
D)All of these types of RNA viruses require RNA Dependent RNA polymerase.

Question 52

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

Question 53

Which of the following uses dsRNA as the genome?

A)Parvovirus
B)Bunyavirus
C)Rotavirus
D)Poxvirus

Question 54

The largest viruses known are the _________.

A)herpesviruses
B)hepadnaviruses
C)adenoviruses
D)mimiviruses

Question 55

Most known plant viruses are RNA viruses.

Question 56

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

Question 57

If a viral gene prevents peptidoglycan units from being linked to lipid carriers,what will happen to the bacterial cell?

A)The cell wall with become stronger leading to virus to enter the lysogenic cycle.
B)The cell wall will weaken,eventually leading to cell lysis.
C)The bacterial cell will start to take on the properties of a Gram Negative cell.
D)Lipid metabolism will become impaired.

Question 58

Which of the following uses ssDNA as the genome?

A)Parvovirus
B)Poliovirus
C)Herpesvirus
D)Poxvirus

Question 59

In which of the following stages of the viral infectious cycle do enveloped viruses usually acquire their envelopes?

A)Penetration
B)Component biosynthesis
C)Assembly
D)Release

Question 60

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

Question 61

Which of the following is a function of reverse transcriptase?

A)It functions as a RNA-dependent DNA polymerase.
B)It functions as a DNA-dependent DNA polymerase.
C)It functions as a ribonuclease to degrade the viral RNA once it has been copied into DNA.
D)All of these are functions of reverse transcriptase.

Question 62

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.

Question 63

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

Question 64

Which of the following must bring in a virion-associated RNA-dependent RNA polymerase when it infects host cells?

A)+ssRNA viruses
B)-ssRNA viruses
C)+dsRNA viruses
D)All of the choices are correct.

Question 65

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.

Question 66

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.

Question 67

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 viruses
B)double-stranded DNA viruses
C)negative-strand RNA viruses
D)single-stranded DNA viruses

Question 68

After infecting the cell,HBV's gapped DNA is released into the nucleus where host _______ enzymes fill the gap and seal the nick,yielding a covalently closed,circular DNA.
or

Question 69

What is unique about reverse transcripatse that makes it different from other DNA polymerases?

A)It is found exclusively in DNA viruses.
B)It has ligase ability built in so host enzymes are not needed to seal up breaks in DNA made during replication.
C)It lacks normal proofreading ability leading to many errors during replication.
D)It manufactures a special tRNA molecule that it uses as a primer to initiate replication.

Question 70

Is reverse transcriptase a RNA-dependent DNA polymerase,or a DNA-dependent DNA polymerase?

A)It is a DNA-dependent DNA polymerase
B)It is a RNA-dependent DNA polymerase.
C)It is both a a DNA-dependent DNA polymerase and a RNA-dependent DNA polymerase.
D)It is neither,reverse transcriptase is actually a DNA-dependent RNA polymerase.

Question 71

Influenza virus adheres to the epithelium of the respiratory system with the aid of _________ and _________ found in its envelope spikes.
or

Question 72

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

Question 73

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

Question 74

Which viral proteins help influenza bind to and enter a host cell?

A)Hemagglutin and Neuraminidase
B)Membrane Protein M2 and Nucleoprotein
C)PB1,PB2 and PA
D)Nuclear export protein and Nucleoprotein

Question 75

Segmented genomes in negative-strand RNA viruses may include two to eight segments each coding for a unique protein.

Question 76

In retroviruses,what helps the newly synthesized dsDNA insert itself into the host genome?

A)Provirus
B)Reverse Transcriptase
C)Integrase
D)Gag polyprotein