Questions and Answers
What are the two groups of DNA?
dsDNA or ssDNA
Is dsDNA enveloped or nonenveloped?
Is ssDNA enveloped or nonenveloped?
What virus families are found in nonenveloped dsDNA?
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What virus families are found in enveloped dsDNA?
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What virus families are found in nonenveloped ssDNA?
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What are the two groups of RNA?
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Is ssRNA positive sense or negative sense?
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Is positive sense ssRNA, nonenveloped or enveloped?
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What is the meaning of positive sense ssRNA viruses?
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What virus families are in positive sense, nonenveloped, ssRNA?
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What virus families are in positive sense, enveloped, ssRNA?
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What is the meaning of negative sense ssRNA?
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Are negative sense ssRNA, enveloped or nonenveloped?
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What virus families are found in negative sense, enveloped, ssRNA?
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Is dsRNA positive sense or negative sense?
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Is dsRNA enveloped or nonenveloped?
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What virus family is found in nonenveloped dsRNA?
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Which is smaller, the genome of RNA viruses or the genome of DNA viruses?
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What does the genome of RNA heavily depend on?
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Why is the genome of RNA more prone to errors (mutations)?
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What are retroviruses?
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What are DNA viruses?
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What are RNA viruses?
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Study Notes
DNA Classification
- DNA viruses are categorized into two groups: double-stranded DNA (dsDNA) and single-stranded DNA (ssDNA).
- dsDNA can be either enveloped or nonenveloped, while ssDNA is exclusively nonenveloped.
Nonenveloped DNA Virus Families
- Nonenveloped dsDNA families include Adenoviridae (associated with common colds and viral meningitis) and Papillomaviridae (linked to warts and cervical cancer).
- The only known family in nonenveloped ssDNA is Parvoviridae, which causes fifth disease and gastroenteritis.
Enveloped DNA Virus Families
- Enveloped dsDNA families are:
- Poxviridae (responsible for smallpox)
- Herpesviridae (causes cold sores, chicken pox, shingles, mononucleosis)
- Hepadnaviridae (includes Hepatitis B and associated liver cancer)
RNA Classification
- RNA viruses are divided into two types: single-stranded RNA (ssRNA) and double-stranded RNA (dsRNA).
- ssRNA can be classified further into positive-sense and negative-sense.
Positive-Sense ssRNA Characteristics
- Positive-sense ssRNA can be either enveloped or nonenveloped and functions as mRNA, enabling direct translation by host ribosomes.
- Families under positive-sense, nonenveloped ssRNA include:
- Picornaviridae (causes the common cold, hepatitis A, polio)
- Caliciviridae (causes gastroenteritis)
- Enveloped positive-sense ssRNA families consist of:
- Coronaviridae (includes SARS)
- Retroviridae (includes HIV)
- Flaviviridae (includes yellow fever, dengue fever, Zika virus, West Nile fever, hepatitis C)
- Togaviridae (includes rubella and encephalitis)
Negative-Sense ssRNA Characteristics
- Negative-sense ssRNA is enveloped and is complementary to mRNA, meaning it must be converted to positive-sense RNA by RNA polymerase before translation can occur.
- Families of negative-sense, enveloped ssRNA viruses include:
- Filoviridae (causes Ebola and Marburg disease)
- Orthomyxoviridae (causes influenza)
- Paramyxoviridae (includes mumps and measles)
- Arenaviridae (associated with Lassa fever)
- Bunyaviridae (associated with hantavirus pulmonary syndrome)
- Rhabdoviridae (associated with rabies)
Additional RNA Information
- dsRNA is neither classified as positive nor negative sense and is always nonenveloped.
- The only known family of dsRNA viruses is Reoviridae, linked to gastroenteritis.
Genome Characteristics and Mutations
- RNA virus genomes are generally smaller than DNA virus genomes.
- RNA viruses rely heavily on host cell proteins and enzymes for replication.
- Higher mutation rates in RNA viruses stem from RNA polymerase's lack of proofreading ability, leading to rapid emergence of new strains.
Retrovirus Definition
- Retroviruses utilize reverse transcriptase to replicate indirectly through a DNA intermediate, producing dsDNA from an ssRNA genome.
Replication Processes
- DNA viruses replicate within the host cell, while RNA viruses replicate at the host cell ribosomes.
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Description
Explore the classification of DNA and RNA viruses with this quiz. You'll learn about different types of DNA, including dsDNA and ssDNA, and their characteristics. Test your knowledge on enveloped and nonenveloped viruses, as well as various virus families related to dsDNA.
