Speaker:王姿文
Date:2016-01-26
view(s): 555
  • 00:06 1.
    17
  • 00:38 2.
    Overview: A Borrowed Life
  • 00:05 3.
    Figure 17.1
  • 00:39 4.
    Concept 17.1: A virus consists of a nucleic acid surrounded by a protein coat
  • 00:22 5.
    Viral Genomes
  • 00:23 6.
    Capsids and Envelopes
  • 01:34 7.
    Figure 17.2
  • 00:27 8.
    Some viruses have membranous envelopes that help them infect hosts These viral envelopes are derived from the host cell’s membrane and contain a combination of viral and host cell molecules
  • 00:23 9.
    Bacteriophages, also called phages, are viruses that infect bacteria They have the most complex capsids found among viruses Phages have an elongated capsid head that encloses their DNA A protein tail piece attaches the phage to the host and injects the ph
  • 00:23 10.
    Concept 17.2: Viruses replicate only in host cells
  • 01:06 11.
    General Features of Viral Replicative Cycles
  • 00:54 12.
    Figure 17.3
  • 00:15 13.
    Replicative Cycles of Phages
  • 00:37 14.
    The Lytic Cycle
  • 00:53 15.
    Figure 17.4-5
  • 00:30 16.
    The Lysogenic Cycle
  • 00:28 17.
    Every time the host divides, it copies the phage DNA and passes the copies to daughter cells A single infected cell can give rise to a large population of bacteria carrying the virus in prophage form An environmental signal can trigger the virus genome to
  • 00:52 18.
    Figure 17.5
  • 00:30 19.
    Replicative Cycles of Animal Viruses
  • 00:22 20.
    Viral Envelopes
  • 01:13 21.
    Figure 17.6
  • 00:52 22.
    Viral DNA that is integrated into the host genome is called a provirus Unlike a prophage, a provirus is a permanent resident of the host cell The host’s RNA polymerase transcribes the proviral DNA into RNA molecules The RNA molecules function both as mRNA
  • 00:37 23.
    RNA as Viral Genetic Material
  • 00:22 24.
    Slide 24
  • 01:41 25.
    Figure 17.7
  • 01:21 26.
    Evolution of Viruses
  • 00:29 27.
    Concept 17.3: Viruses are formidable(厲害強大) pathogens in animals and plants
  • 00:40 28.
    Viral Diseases in Animals
  • 00:56 29.
    A vaccine is a harmless derivative of a pathogen that stimulates the immune system to mount defenses against the harmful pathogen Vaccines can prevent certain viral illnesses Viral infections cannot be treated by antibiotics Antiviral drugs can help to tr
  • 00:47 30.
    Emerging Viruses
  • 00:18 31.
    In 2009 a general outbreak, or epidemic, of a flu-like illness occurred in Mexico and the United States; the virus responsible was named H1N1 H1N1 spread rapidly, causing a pandemic, or global epidemic
  • 00:29 32.
    Figure 17.8
  • 00:57 33.
    Three processes contribute to the emergence of viral diseases The mutation of existing viruses, which is especially high in RNA viruses Dissemination(傳播) of a viral disease from a small, isolated human population, allowing the disease to go unnoticed befo
  • 00:49 34.
    Strains of influenza A are given standardized names The name H1N1 identifies forms of two viral surface proteins, hemagglutinin (H) and neuraminidase (N) There are numerous types of hemagglutinin and neuraminidase, identified by numbers
  • 00:21 35.
    Viral Diseases in Plants
  • 01:42 36.
    Plant viral diseases spread by two major routes Infection from an external source of virus is called horizontal transmission Herbivores, especially insects, pose a double threat because they can both carry a virus and help it get past the plant’s outer la
  • 00:24 37.
    Figure 17.UN01
  • Index
  • Notes
  • Discuss
  • Fullscreen
viruses
Duration: 25:43, Browse: 555, Update: 2020-08-24
    • 00:06 1.
      17
    • 00:38 2.
      Overview: A Borrowed Life
    • 00:05 3.
      Figure 17.1
    • 00:39 4.
      Concept 17.1: A virus consists of a nucleic acid surrounded by a protein coat
    • 00:22 5.
      Viral Genomes
    • 00:23 6.
      Capsids and Envelopes
    • 01:34 7.
      Figure 17.2
    • 00:27 8.
      Some viruses have membranous envelopes that help them infect hosts These viral envelopes are derived from the host cell’s membrane and contain a combination of viral and host cell molecules
    • 00:23 9.
      Bacteriophages, also called phages, are viruses that infect bacteria They have the most complex capsids found among viruses Phages have an elongated capsid head that encloses their DNA A protein tail piece attaches the phage to the host and injects the ph
    • 00:23 10.
      Concept 17.2: Viruses replicate only in host cells
    • 01:06 11.
      General Features of Viral Replicative Cycles
    • 00:54 12.
      Figure 17.3
    • 00:15 13.
      Replicative Cycles of Phages
    • 00:37 14.
      The Lytic Cycle
    • 00:53 15.
      Figure 17.4-5
    • 00:30 16.
      The Lysogenic Cycle
    • 00:28 17.
      Every time the host divides, it copies the phage DNA and passes the copies to daughter cells A single infected cell can give rise to a large population of bacteria carrying the virus in prophage form An environmental signal can trigger the virus genome to
    • 00:52 18.
      Figure 17.5
    • 00:30 19.
      Replicative Cycles of Animal Viruses
    • 00:22 20.
      Viral Envelopes
    • 01:13 21.
      Figure 17.6
    • 00:52 22.
      Viral DNA that is integrated into the host genome is called a provirus Unlike a prophage, a provirus is a permanent resident of the host cell The host’s RNA polymerase transcribes the proviral DNA into RNA molecules The RNA molecules function both as mRNA
    • 00:37 23.
      RNA as Viral Genetic Material
    • 00:22 24.
      Slide 24
    • 01:41 25.
      Figure 17.7
    • 01:21 26.
      Evolution of Viruses
    • 00:29 27.
      Concept 17.3: Viruses are formidable(厲害強大) pathogens in animals and plants
    • 00:40 28.
      Viral Diseases in Animals
    • 00:56 29.
      A vaccine is a harmless derivative of a pathogen that stimulates the immune system to mount defenses against the harmful pathogen Vaccines can prevent certain viral illnesses Viral infections cannot be treated by antibiotics Antiviral drugs can help to tr
    • 00:47 30.
      Emerging Viruses
    • 00:18 31.
      In 2009 a general outbreak, or epidemic, of a flu-like illness occurred in Mexico and the United States; the virus responsible was named H1N1 H1N1 spread rapidly, causing a pandemic, or global epidemic
    • 00:29 32.
      Figure 17.8
    • 00:57 33.
      Three processes contribute to the emergence of viral diseases The mutation of existing viruses, which is especially high in RNA viruses Dissemination(傳播) of a viral disease from a small, isolated human population, allowing the disease to go unnoticed befo
    • 00:49 34.
      Strains of influenza A are given standardized names The name H1N1 identifies forms of two viral surface proteins, hemagglutinin (H) and neuraminidase (N) There are numerous types of hemagglutinin and neuraminidase, identified by numbers
    • 00:21 35.
      Viral Diseases in Plants
    • 01:42 36.
      Plant viral diseases spread by two major routes Infection from an external source of virus is called horizontal transmission Herbivores, especially insects, pose a double threat because they can both carry a virus and help it get past the plant’s outer la
    • 00:24 37.
      Figure 17.UN01
    Location
    Folder name
    普通生物學
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    王姿文
    Division
    生科系
    Create
    2016-01-26 11:20:39
    Update
    2020-08-24 23:37:23
    Browse
    555
    Duration
    25:43