Questions and Answers
What type of polymerase is required by RNA viruses?
Which of the following RNA viruses is associated with haemorrhagic fever?
What type of nucleic acid do enteroviruses contain?
Which of the following viruses is classified as the largest RNA virus?
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Which family includes viruses that cause respiratory infections?
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What type of genetic material can a virus have?
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What is the benefit of a virus having an envelope made from host membrane phospholipids?
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Which component is primarily responsible for protecting the virus's genetic material?
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What describes the overall structure of the complete infectious virus particle?
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How do new virions form within a host cell?
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What characteristic distinguishes nonenveloped viruses from enveloped viruses?
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What role do capsomeres play in a virus?
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What does virion symmetry refer to in virology?
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What is the primary method of replication for Hepadnaviruses?
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Which statement accurately describes the replication location for DNA viruses?
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What feature distinguishes RNA viruses from DNA viruses?
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Which viral characteristic is associated with all (-) RNA viruses?
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Which statement accurately describes the infectiousness of DNA viruses compared to RNA viruses?
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How do segmented RNA viruses change their genetic material?
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What is a common feature of DNA viruses compared to RNA viruses?
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What is NOT a criterion for the classification of viruses?
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What is the defining characteristic of Group 4 viruses in the Baltimore classification?
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How is negative-sense RNA synthesized for protein production?
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Which Baltimore classification group does not act as mRNA?
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Which statement about transcription in Group 4 viruses is correct?
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Which of the following is NOT true in the context of SS Retro RNA?
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What type of genome does Group 3 in the Baltimore classification have?
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What is the impact of a virus categorized under Group 1?
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What does the Baltimore classification system primarily classify?
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Which process is necessary for negative-sense RNA viruses to produce mRNA?
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What is one of the characteristics of single-stranded RNA viruses?
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Which of the following viruses is classified as a Bunyavirus?
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What is the primary replication strategy of Retroviruses?
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Which virus is associated with gastroenteritis?
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How does the influenza virus enter a host cell?
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What type of genetic material does Calicivirus possess?
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Which of the following statements is true regarding Rhabdoviruses?
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Which characteristic distinguishes Paramyxoviruses?
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What is a key feature of Ebola virus?
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What distinguishes the genetic material of Reoviruses?
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What type of RNA is associated with Hanta viruses?
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Which of the following correctly describes the Baltimore classification of viruses?
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What is unique about the replication of the influenza virus?
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What type of disease is primarily linked to Arenaviruses?
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Which of the following viruses is classified under the family of Caliciviruses?
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Study Notes
Virus Characteristics
- Viruses are obligate intracellular parasites, requiring host cells for reproduction.
- Contain either DNA or RNA as genetic material, never both.
- Viral genetic material directs the synthesis of new virions within host cells.
- New virions assemble from building blocks in host cells and spread to infect other cells.
Basic Virus Components
- Virion: Complete infectious virus particle.
- Capsid: Protein coat that protects nucleic acids and has antigenic properties.
- Capsomeres: Protein subunits forming the capsid; more stable than lipids, making non-enveloped viruses generally more stable.
- Envelope: Phospholipid membrane derived from the host cell, facilitating entry into host cells and featuring proteins that enable specific adhesion via receptor binding domains.
Virus Replication Process
- Virus binds to host cell using receptor spikes.
- Entry occurs through fusion with the host membrane or endocytosis.
- The virus utilizes host cell machinery for replication and protein synthesis.
- Influenza virus replication occurs in the nucleus due to its segmented genome.
- HIV integrates its genetic material into the host genome, distinguishing it from other viruses.
Baltimore Classification
- Developed by David Baltimore, classifies viruses by nucleic acid type and replication strategies.
- Types include:
- DS DNA: Double-stranded DNA viruses.
- SS DNA: Single-stranded DNA viruses.
- DS RNA: Double-stranded RNA viruses.
- SS RNA (+): Positive-sense single-stranded RNA viruses, can act directly as mRNA.
- SS RNA (-): Negative-sense RNA viruses, must be transcribed to produce mRNA.
- SS Retro RNA (+): Retroviruses, which synthesize DNA from RNA through reverse transcription.
Virus Dynamics
- DNA viruses: Generally permanent, replicate in the nucleus, and their genomic material is infectious.
- RNA viruses: Short-lived, primarily replicate in the cytoplasm (exceptions exist for certain groups).
- All negative-sense RNA viruses have envelopes and contain RNA polymerase for replication.
- Segmented RNA viruses possess the ability to alter their composition through reassortment.
Classification Summary
- Classification of viruses considers nucleic acid type, strand number, genome polarity, capsid symmetry, presence of envelope, and other genetic and antigenic properties.
Viral Release Mechanisms
- Viruses exit host cells through either lysis (cell destruction) or budding (acquisition of an envelope).
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Description
Explore the fundamental properties and behavior of viruses as distinct biological entities. This quiz covers their characteristics, genetic material, and reproduction within a host cell. Test your understanding of these infectious agents and their unique lifecycle.