Chapter 6D

• Viruses, Virions, Prions


  Infectious agents

  non-living obligate aerobes
• True


  True or False: Viruses relies on host cells for energy metabolic intermediates, and protein synthesis.
• Virion


  refer to a single infective viral particle.
• independent


  Viruses possess their own genomes and thus they are _____________ of the host's genome
• Capsid


  Protein shell of a virus that encloses its genetic material
• Non-enveloped viruses


  Viruses formed from only NA and a capsie
• Enveloped viruses

  Viruses formed with a nucleic-acid packed capsid surrounded by a lipid layer
• True


  True or false: Viruses have 2 kinds based on general composition which are non-enveloped and enveloped virus
• viral envelope


  Small portion of phospholipid membrane obtained as the virion buds from a host cell. It is an important part of infection as it makes contact with host cell. It may either be intracellular or cytoplasmic in origin
• Ebola


  Example of an enveloped viruses that use proteins on the virion's envelope to attach to and infect animal cells in which the cytoplasmic membrane is directly exposed to the environment.
• Cell wall

  Plant and bacterial cells are surrounded by a _________

  outside the cytoplasmic membrane, and thus few examples of enveloped viruses are known in these organisms
• Capsomeres


  Protein subunits arranged in a precise and

  highly repetitive manner around the nucleic acid
• Larger


  Pandoravirus salinus and Pithovirus sibericum are example of _______ species of viruses
• 20nm-900nm


  Size of viruses
• nucleocapsid


  capsid + enclosed nucleic acid
• host


  Property of viruses is to infect eukaryotic and prokaryotic cells like bacteria, algae, plants, animals and humans. These example are called its __________
• Viral symmetry


  Helical, icosahedral-spherical, and complex are viruses groups based on their
• NA;capsomeres

  The lengths of helical viruses are determined by the length of the ________; and the width of the helical virion is determined by the size and packaging of the ____________
• flexible;rigid

  In helical viruses, - animal viruses have ________ nucleocapsids which are wound into a ball inside the envelope; while plant viruses have __________ nucleocapsids
• Helical

  Appear rod-shaped. In this symmetry, protein subunits bound in periodic way to viral NA, winding it to a helix
• 20;12


  Icosahedral-spherical symmetry is with ____ triangular faces and _____ vertices. These are the shape of poliovirus, rhinovirus, adenovirus, and herpes that resembles a soccer ball
• Complex

  asymmetrical structures complex, with the virion consisting of several parts each displaying its own shape and symmetry. Some examples are T4 and lambda bacteriophage, e.coli, and smallpox
• True


  True or false:

  
  

  Nucleic acid in viruses can :

  • either DNA or RNA

  • linear or circular

  • single or double- stranded (singles can be plus or minus sense)

  • segmented (composed of multiple pieces) or non- segmented
• Proteins


  This is used as a protection against

  inactivation by nucleases, participate in attachment to

  host, facilitate transfer of viral nucleic acid from 1 host cell to another, initiation of virus replication, provide structural symmetry, and determine antigenic

  property
• viral protein


  In RNA viruses, specific _________ must also enter the host cell along with the viral genome. Only when this molecule begin to appear from the translation of viral transcripts, can viral assembly begin.
• Early proteins


  Are typically enzymes and are therefore synthesized in relatively small amounts. These include not only nucleic acid polymerases but also proteins that function to shut down host transcription and translation.
• Late proteins


  late proteins are typically structural components of the virion and other proteins that are not needed until virion assembly begins, and

  these are made in much larger amounts
• Lipids


  found in envelopes and derived from host cell
• Plasma membrane

  Some animal viruses are released from the host cell by an extrusion process that coats the virus with a layer of the host cell's ______________. That layer becomes the viral envelope.
• Carbohydrates


  Not derived from host cells. They are present as glycoproteins in envelope, they are virus-coded, are the antigen, receptors, and spike made of.
• Spike

  Are carbohydrate-protein complexes that project from

  the surface of the envelope. They help some viruses attach to host cells. It gives ability to influenza virus to clump red blood cells.
• growing


  Host cells need to be ______ in order for viruses to replicate in them.
• Embryonated eggs

  Cultivation of viruses process where viral growth indicated by death of embryo, embryo cell damage, or formation of lesions
• Animal inoculation


  Type of cultivation which is the most method used for viral isolation and for studies on their pathogenesis and oncogenesis
• True or false: animal is observed for signs of disease and immune response or is killed to examine living tissues
• Cell cultures


  Virus cultivation process that is started by treating a slice of animal tissue with enzymes that separate the individual cells. These cells are suspended in a solution that provides the osmotic pressure, nutrients, and growth factors needed for the cells to

  grow.
• monolayer;deteriorate

  Normal cells tend to adhere to the glass or plastic container and reproduce to form a ________; In the presence of virus, cause it to ___________ as they multiply.
• interferons


  Result in the cell culture says that there is an adsorption of erythrocytes to infected cells (hemagglutination), plaque. The cell culture cultivation means that there is an appearance of a virus-coded proteins calls
• cytopathic effect

  Distinct observable cell abnormalities (deterioration) due to viral infection in cell cultures. Which can:

  - include loss of adherence to the

  surface of the container

  - changes in cell shape from flat to round

  - shrinkage of the nucleus

  - vacuoles in the cytoplasm

  - fusion of cytoplasmic membranes and the formation of multinucleated syncytia, inclusion bodies in the nucleus or cytoplasm

  - complete cell lysis.
• carcinomas and sarcomas


  Further pathological changes in CPE which include viral disruption of the host genome and altering normal cells into transformed cells, which are the types of cells associated with ___________