18/19 Flashcards


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1

) Which of the following accounts for someone who has had a herpesvirus-mediated cold sore or genital sore getting flare-ups for the rest of his or her life?
A) re-infection by a closely related herpesvirus of a different strain
B) re-infection by the same herpesvirus strain
C) co-infection with an unrelated virus that causes the same symptoms
D) copies of the herpesvirus genome permanently maintained in host nuclei
E) copies of the herpesvirus genome permanently maintained in host cell cytop

D

2

In many ways, the regulation of the genes of a particular group of viruses will be similar to the regulation of the host genes. Therefore, which of the following would you expect of the genes of the bacteriophage?
A) regulation via acetylation of histones
B) positive control mechanisms rather than negative
C) control of more than one gene in an operon
D) reliance on transcription activators
E) utilization of eukaryotic polymerases

C

3

Why do RNA viruses appear to have higher rates of mutation?
A) RNA nucleotides are more unstable than DNA nucleotides.
B) Replication of their genomes does not involve proofreading.
C) RNA viruses replicate faster.
D) RNA viruses can incorporate a variety of nonstandard bases.
E) RNA viruses are more sensitive to mutagens.

B

4

You isolate an infectious substance that is capable of causing disease in plants, but you do not know whether the infectious agent is a bacterium, virus, viroid, or prion. You have four methods at your disposal that you can use to analyze the substance in order to determine the nature of the infectious agent.

I. treating the substance with nucleases that destroy all nucleic acids and then determining whether it is still infectious
II. filtering the substance to remove all elements smaller than what can be easily seen under a light microscope
III. culturing the substance by itself on nutritive medium, away from any plant cells
IV. treating the sample with proteases that digest all proteins and then determining whether it is still infectious

37) Which treatment could definitively determine whether or not the component is a viroid?
A) I
B) II
C) III
D) IV
E) first II and then III

A

5

You isolate an infectious substance that is capable of causing disease in plants, but you do not know whether the infectious agent is a bacterium, virus, viroid, or prion. You have four methods at your disposal that you can use to analyze the substance in order to determine the nature of the infectious agent.

I. treating the substance with nucleases that destroy all nucleic acids and then determining whether it is still infectious
II. filtering the substance to remove all elements smaller than what can be easily seen under a light microscope
III. culturing the substance by itself on nutritive medium, away from any plant cells
IV. treating the sample with proteases that digest all proteins and then determining whether it is still infectious

38) If you already knew that the infectious agent was either bacterial or viral, which treatment would allow you to distinguish between these two possibilities?
A) I
B) II
C) III
D) IV
E) either II or IV

C

6

You isolate an infectious substance that is capable of causing disease in plants, but you do not know whether the infectious agent is a bacterium, virus, viroid, or prion. You have four methods at your disposal that you can use to analyze the substance in order to determine the nature of the infectious agent.

I. treating the substance with nucleases that destroy all nucleic acids and then determining whether it is still infectious
II. filtering the substance to remove all elements smaller than what can be easily seen under a light microscope
III. culturing the substance by itself on nutritive medium, away from any plant cells
IV. treating the sample with proteases that digest all proteins and then determining whether it is still infectious

39) Which treatment would you use to determine if the agent is a prion?
A) I only
B) II only
C) III only
D) IV only
E) either I or IV

D

7

43) Which of the following characteristics, structures, or processes is common to both bacteria and viruses?
A) metabolism
B) ribosomes
C) genetic material composed of nucleic acid
D) cell division
E) independent existence

c

8

20) Antiviral drugs that have become useful are usually associated with which of the following properties?
A) ability to remove all viruses from the infected host
B) interference with viral replication
C) prevention of the host from becoming infected
D) removal of viral proteins
E) removal of viral mRNAs

B

9

47) Mutations in which of the following genes lead to transformations in the identity of entire body parts?
A) morphogens
B) segmentation genes
C) egg-polarity genes
D) homeotic genes
E) inducers

D

10

Tumor-suppressor genes
A.

are frequently overexpressed in cancerous cells.
B.

are cancer-causing genes introduced into cells by viruses.
C.

can encode proteins that promote DNA repair or cell-cell adhesion.
D.

often encode proteins that stimulate the cell cycle.
E.

do all of these.

C

11

18) What are prions?
A) mobile segments of DNA
B) tiny molecules of RNA that infect plants
C) viral DNA that has had to attach itself to the host genome
D) misfolded versions of normal brain protein
E) viruses that invade bacteria

D

12

19) Which of the following is the best predictor of how much damage a virus causes?
A) ability of the infected cell to undergo normal cell division
B) ability of the infected cell to carry on translation
C) whether the infected cell produces viral protein
D) whether the viral mRNA can be transcribed
E) how much toxin the virus produces

A

13

20) Antiviral drugs that have become useful are usually associated with which of the following properties?
A) ability to remove all viruses from the infected host
B) interference with viral replication
C) prevention of the host from becoming infected
D) removal of viral proteins
E) removal of viral mRNAs

B

14

14) Which of the following is characteristic of the lytic cycle?
A) Many bacterial cells containing viral DNA are produced.
B) Viral DNA is incorporated into the host genome.
C) The viral genome replicates without destroying the host.
D) A large number of phages is released at a time.
E) The virus-host relationship usually lasts for generations.

D

15

Why do RNA viruses appear to have higher rates of mutation?
A) RNA nucleotides are more unstable than DNA nucleotides.
B) Replication of their genomes does not involve the proofreading steps of DNA replication.
C) RNA viruses replicate faster.
D) RNA viruses can incorporate a variety of nonstandard bases.
E) RNA viruses are more sensitive to mutagens.

B