3: Viruses

• Disadvantage of Using Viruses

  Pathogenic nature; Harm to humans, plants, and animals (Cause disease).
• Virulent Phage


  A phage that reproduces only by a lytic cycle.
• Phage (Bacteria) Viruses

  Exchibit lytic and lysogenic cycles.
• Capsomere

  The subunit of a virus capsid
• Capsid


  Outer protein coat of a virus
• Nucleic Acid


  A complex organic substance present in living cells, especially DNA or RNA, whose molecules consist of many nucleotides linked in a long chain.
• Advantages of Viruses

  Useful in delivering genes for gene therapy research, but many are pathogenic causing harm to humans, plants, and animals
• Marine Viruses


  Kill phytoplankton, with over 200,000 types discovered in the ocean
• ssRNA

  Single-stranded RNA viral genetic material
• dsRNA


  Double-stranded RNA viral genetic material
• ssDNA

  Single-stranded DNA viral genetic material
• dsDNA


  Double-stranded DNA viral genetic material
• Prophage


  Integrated viral DNA in a bacterium's chromosome during the lysogenic cycle
• Retrovirus


  Single-stranded RNA virus containing an enzyme that reverses genetic transcription to synthesize DNA, unique to retroviruses
• Lysogenic Cycle


  Phage genome replicates without destroying the host, and viral DNA is incorporated into the bacterial chromosome
• Lytic Cycle


  Characterized by the death of the host cell and release of progeny viruses
• Viral Cycle


  The process where viral genome uses host cell machinery to manufacture viral proteins and self-assembles into new viruses
• Viral Genomes

  Consist of either DNA or RNA, determining if the virus is a DNA virus or an RNA virus
• Bacteriophages


  Viruses infecting bacteria, possessing the most complex structure

  
• Icosahedral (Cubic Symmetry)


  Virus with a polyhedral shape, sometimes with spikes at each vortex

  
• Helical Symmetry


  Virus with a shape resembling a filament of a rigid rod

  
• Enveloped Virus


  Virus surrounded by an envelope, aiding infection and protecting nucleic acid
• Nucleocapsid

  Core of genetic material (nucleic acid) combined with protein coat (capsid)
• Covid-19


  Officially named SARS-CoV-2, belonging to the coronavirus family
• Tree of Life

  Viruses cannot be included due to lack of shared characteristics with cells and absence of inherited characteristics from ancestors
• Viruses

  Intracellular parasites lacking metabolic activities and living characteristics
• Virions are the infectious form of viruses.
• The nucleocapsid is composed of protein subunits that surround the genome, which can be single-stranded or double-stranded DNA or RNA.
• Bacteriophages are viruses that infect bacteria.