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General Biology: Viruses

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Terms in this set (21)

  • What is a virus?
    A virus is a small infectious agent that requires a host cell to replicate, consisting of genetic material enclosed in a protein coat called a capsid.
  • What is a capsid?
    The capsid is the protein coat that covers the viral genome and can take many different forms.
  • What is a capsomere?
    A capsomere is a subunit of the capsid, the protein coat of a virus.
  • What types of genetic material can viruses have?
    Viruses may contain double-stranded DNA, single-stranded DNA, double-stranded RNA, or single-stranded RNA.
  • What are bacteriophages?
    Bacteriophages are viruses that infect bacteria and often have complex capsid structures.
  • What is a viral envelope?
    A viral envelope is an accessory structure in many animal viruses, often derived from the host cell's membrane.
  • What determines a virus's host range?
    The host range is the collection of hosts a virus can infect, determined by the virus's surface proteins binding to specific receptors on host cells.
  • How do viruses enter host cells?
    Viruses enter host cells by injecting their genome, endocytosis, or membrane fusion.
  • What happens during viral replication?
    The virus hijacks the host's machinery to produce viral nucleic acids and proteins, which assemble into new viruses.
  • What is the lytic cycle?
    The lytic cycle is viral replication that ends with the host cell's death and release of new viruses.
  • What is a virulent phage?
    A virulent phage replicates only by the lytic cycle, causing host cell destruction.
  • What is the lysogenic cycle?
    The lysogenic cycle replicates viral DNA integrated into the host genome without killing the host.
  • What is a temperate phage?
    A temperate phage can replicate via both the lytic and lysogenic cycles.
  • What is a prophage?
    A prophage is viral DNA integrated into the bacterial chromosome during the lysogenic cycle.
  • How do animal viruses typically replicate?
    Animal viruses often have envelopes and RNA genomes; they enter cells via receptor recognition and replicate using viral RNA polymerase.
  • What is a retrovirus?
    A retrovirus has an RNA genome and uses reverse transcriptase to transcribe its RNA into DNA, which integrates into the host genome.
  • What is reverse transcriptase?
    Reverse transcriptase is an enzyme that catalyzes the transcription of viral RNA into DNA.
  • What is a provirus?
    A provirus is viral DNA integrated into the host's genome in animal cells.
  • How do double-stranded DNA viruses replicate?
    They enter the nucleus and replicate their genomes often during the S phase of the host cell cycle.
  • What are viroids?
    Viroids are small, circular, single-stranded RNA pathogens that infect plants and disrupt growth without encoding proteins.
  • What are prions?
    Prions are infectious proteins that cause brain diseases by inducing misfolding of normal proteins.