Viruses Chapter 26 Verified Test Bank

Prescott's Microbiology, 11e (Willey)

Chapter 26 Viruses

1) Rubulavirus falls under which group of the ICTV nomenclature system?

A) Order

B) Family

C) Subfamily

D) Genus

2) 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

3) 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

4) 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

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

6) 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

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

8) Bacteriophage that only exhibit lytic replication cycles are called ________ phages.

A) temperate

B) virulent

C) intemperate

D) lytigate

9) 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) twofold rotationally symmetrical

B) a linear repeat

C) circularly permuted

D) linearly palindromic

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

A) Poxvirus

B) Poliovirus

C) Influenza virus

D) Rabies virus

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

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

A) Lysozyme

B) Protection exonucleases

C) Restriction endonucleases

D) Modification methylases

13) A ________ is a sequence-specific recognition protein with endonuclease activity.

A) DNA helicase

B) terminal transferase

C) restriction endonuclease

D) DNA ligase

14) 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.

15) 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

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

17) 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

18) 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

19) If the bacteriophage lambda enters into a host cell and integrates its genome into the host cell, the phage has entered the ________ cycle.

20) 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

21) 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.

22) 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

23) 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

24) 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.

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

26) 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.

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

28) 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

29) 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

30) Glycosylation of hydroxymethylcytosine residues protects phage T4 DNA from cleavage by bacterial restriction enzymes.

31) 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 choices are correct.

32) 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.

33) 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

34) 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

35) ________ is an unusual base found in the DNA of T4 phages.

36) 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.

37) 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. 

38) 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.

39) 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

40) The largest viruses known are the ________.

A) herpesviruses

B) hepadnaviruses

C) adenoviruses

D) mimiviruses

41) Viruses infecting algae have never been detected.

42) 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.

43) The genome of phiX174 is ________.

A) double-stranded DNA

B) single-stranded DNA

C) double-stranded RNA

D) single-stranded RNA

44) Parvoviruses are among the simplest known DNA viruses of animals.

45) Which of the following uses ssDNA as the genome?

A) Parvovirus

B) Poliovirus

C) Herpesvirus

D) Poxvirus

46) 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. 

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

48) 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

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

A) replicase

B) ligase

C) helicase

D) transcriptase

50) When RNA-dependent RNA polymerase is copying the genome it is functioning as a ________.

A) replicase

B) ligase

C) helicase

D) transcriptase

51) Which of the following uses dsRNA as the genome?

A) Parvovirus

B) Bunyavirus

C) Rotavirus

D) Poxvirus

52) 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.

53) 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

54) 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

55) 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).

56) Most known plant viruses are RNA viruses.

57) 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

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

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

60) 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.

61) How many times does a minus-strand RNA virus have to replicate its genome to produce a copy ready for assembly into a new virion?

A) Once

B) Twice

C) Three separate times

D) It first requires reverse transcription

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

63) HIV uses a 5' cap structure to distinguish copies of the genome destined for translation versus copies used for replication.

64) 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

65) How do HIV virions acquire their envelope?

A) When they exit the host via budding

B) When they exit the host after lysis

C) Before the cell undergoes lysis

D) HIV does not have an envelope.

66) 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

67) The host cell enzyme that HIV relies on for the synthesis of its genome is a(n) ________.

A) DNA-dependent DNA polymerase

B) DNA-dependent RNA polymerase

C) RNA-dependent RNA polymerase

D) reverse transcriptase

68) 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.

69) HIV makes use of overlapping genes that are processed in different reading frames by the process of ribosomal ________.

A) frameshifting

B) reverse transcription

C) integrase

D) provirus

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

A) Provirus

B) Reverse transcriptase

C) Integrase

D) Gag polyprotein

71) The HIV viral envelope protein gp120 binds to the host cell CD4 receptor.

72) 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

73) 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.

74) 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. 

75) 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. 

76) 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.

77) During viral reproduction, HBV form an immature core particle made up of which components?

A) Reverse transcriptase

B) Plus-strand RNA pregenome

C) Core protein

D) All of these make up the immature core particle.

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

79) 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