Questions and Answers
What is a virion?
A complete virus particle outside of the host cell
Why do viruses need to get into the host cell to survive?
They don't have their own metabolic machinery
What encases the newly replicated viral genome?
Viral structural proteins
What is the genetic material of a virion?
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What is the function of a virus's capsid?
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Which of the following is a mechanism for viral budding?
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What determines virus classification?
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What is a characteristic of viruses with dsDNA genomes?
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Which enzyme is packaged in the virion of viruses with a reverse transcriptase (RT) step in their replication cycle?
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What is a characteristic of most "-" RNA genomes?
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Which cellular process is triggered by a low pH during virus entry?
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How are fusion proteins involved in virus-induced membrane fusion?
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What is the main strategy for viruses to pass through the nuclear membrane?
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How do non-enveloped viruses transfer their genetic material from endosome to cytoplasm?
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What is the function of macropinosomes in virus entry?
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What are the characteristics used to determine viruses?
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What did the Hershey and Chase experiment demonstrate?
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What do RNA viruses pose challenges for?
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What do bacteriophages infect?
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What is commonly used for assaying viruses due to their visible and stable nature?
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What is the process of developing viral envelopes at the cell membrane called?
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What prevents dehydration and viral aggregation in viral envelopes?
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What is the function of core proteins in viral assembly?
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Where are envelope proteins synthesized and inserted?
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What directs the specificity for incorporation of viral genomes into virions?
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Which of the following is true about dsRNA viruses?
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What is a characteristic of viroids?
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What does reverse transcriptase do in viral replication?
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What is a common feature of satellite viruses and satellite nucleic acids?
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What is the role of capsids in viral replication?
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What is the role of viral structural proteins in the viral replication cycle?
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Why do viruses need to rely on host cells for survival?
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What is the composition of a virion?
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What happens to virus particles once inside the host cell?
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What is the genetic material of a virus?
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What is the function of a virion's lipid envelope?
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What is the main role of viruses' genetic material inside the host cell?
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What is the function of the capsid in a virus particle?
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What is the role of viral proteins during virus entry into the host cell?
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What is the function of the lipid envelope in some virions?
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What is the significance of the fact that viruses are considered the simplest and smallest forms of life?
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What is the primary function of viral structural proteins?
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What is the main issue with having an RNA genome?
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What is the role of reverse transcriptase in retroviruses?
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What did the Hershey and Chase experiment demonstrate?
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What distinguishes viruses from other microorganisms according to early studies?
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What is the main reason bacteriophages are used as a model system?
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Which enzyme is commonly encoded by most RNA viruses?
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What is the significance of viruses in the study of biology?
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What is the primary role of viruses in various ecosystems?
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What was the outcome of the filtration experiment with the agent causing mosaic disease?
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What is the significance of the study of bacteriophages?
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What is the function of bacteriophages in genetic mapping?
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What is the significance of the RNA genome in viruses?
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Study Notes
Viral Genome Structure and Evolution
- Some viruses have segmented or unsegmented genomes
- dsRNA viruses have fragmented genomes and capsids with icosahedral symmetry
- Capsids act as intracellular machines for transcription
- dsRNA viruses tend to have a broad host range
- Satellite viruses and satellite nucleic acids require a helper virus to replicate
- Viroids do not encode for proteins and replicate independent of other viruses
- Viruses may have originated alongside host cells
- Reverse transcriptase produces DNA from RNA
- Limited number of viral genes encode for structural proteins and enzymes
- Viruses have to evade host cell defense barriers and the immune system
- Bacteriophages and plant viruses have different entry mechanisms than animal viruses
- Enveloped and non-enveloped viruses have distinct penetration strategies