Textbook Question
Identify the viral family that infects skin, mucosa, and nerve cells; causes infections that can recur because of latency; and has polyhedral geometry.
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Ch. 13 - Viruses, Viroids, and Prions
Tortora14th EditionMicrobiology: An IntroductionISBN: 9780138200398
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Table of contents
- Ch. 1 - The Microbial World and You18
- Ch. 2 - Chemical Principles20
- Ch. 3 - Observing Microorganisms Through a Microscope18
- Ch. 4 - Functional Anatomy of Prokaryotic and Eukaryotic Cells21
- Ch. 5 - Microbial Metabolism20
- Ch. 6 - Microbial Growth20
- Ch. 7 - The Control of Microbial Growth20
- Ch. 8 - Microbial Genetics19
- Ch. 9 - Biotechnology & DNA Technology20
- Ch. 10 - Classification of Microorganisms15
- Ch. 11 - The Prokaryotes: Domains Bacteria and Archaea14
- Ch. 12 - The Eukaryotes: Fungi, Algae, Protozoa, and Helminths17
- Ch. 13 - Viruses, Viroids, and Prions20
- Ch. 14 - Principles of Disease and Epidemiology21
- Ch. 15 - Microbial Mechanisms of Pathogenicity19
- Ch. 16 - Innate Immunity: Nonspecific Defenses of the Host20
- Ch. 17 - Adaptive Immunity: Specific Defenses of the Host20
- Ch. 18 - Practical Applications of Immunology20
- Ch. 19 - Disorders Associated with the Immune System19
- Ch. 20 - Antimicrobial Drugs19
- Ch. 21 - Microbial Diseases of the Skin and Eyes21
- Ch. 22 - Microbial Diseases of the Nervous System19
- Ch. 23 - Microbial Diseases of the Cardiovascular and Lymphatic Systems20
- Ch. 24 - Microbial Diseases of the Respiratory System20
- Ch. 25 - Microbial Diseases of the Digestive System20
- Ch. 26 - Microbial Diseases of the Urinary and Reproductive Systems19
- Ch. 27 - Environmental Microbiology20
- Ch. 28 - Applied and Industrial Microbiology19
Tortora14th EditionMicrobiology: An IntroductionISBN: 9780138200398Not the one you use?Change textbook
Chapter 13, Problem 9
Which of the following does not initiate DNA synthesis?
a. A double-stranded DNA virus (Poxviridae)
b. A DNA virus with reverse transcriptase (Hepadnaviridae)
c. An RNA virus with reverse transcriptase (Retroviridae)
d. A single-stranded RNA virus (Togaviridae)
e. None of the above
Verified step by step guidance1
Step 1: Understand the process of DNA synthesis initiation in viruses. DNA synthesis typically requires a primer or a mechanism to start the formation of a new DNA strand from a template.
Step 2: Analyze each virus type in the options to determine if it initiates DNA synthesis:
- Poxviridae (double-stranded DNA virus) directly uses its DNA for replication.
- Hepadnaviridae (DNA virus with reverse transcriptase) synthesizes DNA from an RNA intermediate.
- Retroviridae (RNA virus with reverse transcriptase) synthesizes DNA from RNA.
- Togaviridae (single-stranded RNA virus) generally does not synthesize DNA as part of its replication cycle.
Step 3: Recall that reverse transcriptase is an enzyme that synthesizes DNA from an RNA template, so viruses with this enzyme initiate DNA synthesis through reverse transcription.
Step 4: Recognize that single-stranded RNA viruses like Togaviridae replicate their RNA genome without producing DNA, so they do not initiate DNA synthesis.
Step 5: Conclude which virus type does not initiate DNA synthesis based on the above analysis.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
DNA Synthesis Initiation in Viruses
DNA synthesis initiation refers to the process by which a virus begins replicating its DNA genome. Some viruses carry enzymes or use host machinery to start DNA replication, often requiring primers or reverse transcription. Understanding which viral families initiate DNA synthesis helps determine their replication strategies.
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Animal Viruses: DNA Virus Synthesis & Replication
Role of Reverse Transcriptase in Viral Replication
Reverse transcriptase is an enzyme that synthesizes DNA from an RNA template. Viruses like Retroviridae and Hepadnaviridae use reverse transcriptase to convert their RNA or RNA intermediates into DNA, initiating DNA synthesis indirectly. This enzyme is key to understanding how certain RNA viruses replicate via a DNA intermediate.
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04:28Animal Viruses: Reverse-Transcribing Virus Synthesis & Replication
Differences Between DNA and RNA Viruses
DNA viruses typically replicate their genomes directly as DNA, while RNA viruses replicate RNA genomes and may or may not involve DNA intermediates. Single-stranded RNA viruses like Togaviridae generally do not initiate DNA synthesis, as their replication relies on RNA-dependent RNA polymerase, not DNA synthesis.
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04:36Replication of (-) Single Strand RNA Viruses
Related Practice
Textbook Question
Place the following in the order in which they are found in a host cell: (1) capsid proteins;
(2) infective phage particles; (3) phage nucleic acid.
a. 1, 2, 3
b. 3, 2, 1
c. 2, 1,3
d. 3, 1, 2
e. 1, 3, 2
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Textbook Question
Plant viruses can’t penetrate intact plant cells because (a) ________; therefore, they enter cells by (b) ________. Plant viruses can be cultured in (c) ________.
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Textbook Question
A viral species is not defined on the basis of the disease symptoms it causes. The best example of this is
a. polio.
b. rabies.
c. hepatitis.
d. chickenpox and shingles.
e. measles.
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Textbook Question
Persistent viral infections such as (a) ________ might be caused by (b) ________ that are (c) ________.
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