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  • 病毒复制 - 高级

    lesson content

    If are not living, how do they make more of themselves?
    ::如果不活着,他们又如何自我充实呢?

    How do viruses reproduce or replicate? They need a host . And the host does all the work for the virus.
    ::病毒是如何复制或复制的?它们需要一个主机。主机为病毒做所有的工作。

    Replication of Viruses
    ::病毒复发

    Viral do not grow through , because they are not ; instead, they use the machinery and metabolism of a host cell to produce multiple copies of themselves. Even though a virus sometimes will not kill the host cell, it can still affect the cell's .
    ::病毒不会生长, 因为它们不是 ; 相反,它们利用宿主细胞的机器和新陈代谢 来生产多种副本。 尽管病毒有时不会杀死宿主细胞,但它仍然可以影响宿主细胞。

    Replication of DNA Viruses
    ::DNA病毒的复制

    A DNA virus is a virus that uses as its genetic material and replicates using a DNA-dependent DNA polymerase. The is usually double-stranded DNA but may also be single-stranded DNA. The DNA of DNA viruses is transcribed into mRNA by the host cell. The viral mRNA is then translated into viral by the host cell. These viral proteins then assemble to form new viral particles.
    ::DNA病毒是一种病毒,其基因材料是使用依靠DNA的DNA聚合酶复制的。它通常是双层DNA,但也可能是单层DNA。DNA病毒的DNADNA由主机细胞转录到 mRNA。病毒MRNA随后由主机细胞转化成病毒。这些病毒蛋白质随后组装成新的病毒粒子。

    Replication of RNA Viruses
    ::RNA病毒的复制

    An RNA virus is a virus that uses ribonucleic acid (RNA) as its genetic material. Their nucleic acid is usually single-stranded but may also be double-stranded RNA. Important human pathogenic RNA viruses include the Severe Acute Respiratory Syndrome (SARS) virus, Influenza virus, and Hepatitis C virus. RNA viruses can be placed into different groups depending on their type of replication.
    ::RNA病毒是一种使用核糖核酸(RNA)作为遗传材料的病毒,其核酸通常是单扎的,但也可能是双扎的RNA。 重要的人类致病性RNA病毒包括严重急性呼吸系统综合症(萨斯)病毒、流感病毒和丙型肝炎病毒。 RNA病毒可以根据其复制类型分为不同的组别。

    • Some RNA viruses have their genome used directly as if it were messenger RNA (mRNA). The viral RNA is translated directly into new viral proteins by the host cell, after infection by the virus.
      ::一些RNA病毒的基因组被直接使用,仿佛是送信的RNA(MRNA)病毒。 病毒RNA在感染病毒后,由宿主细胞直接转化为新的病毒蛋白。
    • Some RNA viruses carry which allow their RNA genome to act as a template for the host cell to a form viral mRNA.
      ::一些RNA病毒携带,使得其RNA基因组可以作为主机细胞的模板,形成病毒型MRNA。
    • Retroviruses use DNA intermediates to replicate. Reverse transcriptase , a viral enzyme that comes from the virus itself, converts the viral RNA into a complementary strand of DNA, which is copied to produce a double stranded molecule of viral DNA. This viral DNA is then transcribed and translated by the host cell's machinery, directing the formation of new virions . Normal involves the synthesis of RNA from DNA; hence, reverse transcription is the reverse of this process. This is an exception to the central dogma of molecular biology .
      ::Retro病毒使用DNA中间体复制。 逆向转录酶是病毒本身产生的病毒酶,它把病毒RNA转换成一种互补的DNA链条,复制后生成一个双倍受困的病毒DNA分子。 然后,这种病毒DNA由主机转录和翻译,引导新病毒的形成。 正常状态涉及DNA合成RNA; 因此,逆向转录是这一过程的反向。 这是分子生物学核心教条的例外 。

    Reverse-Transcribing Viruses
    ::反反制病毒

    A reverse-transcribing virus is any virus which replicates using reverse transcription, the formation of DNA from an RNA template. Some reverse-transcribing viruses have genomes made of single-stranded RNA; these viruses use a DNA intermediate to replicate. Others in this group have genomes that have double-stranded DNA; these viruses use an RNA intermediate during genome replication. The retroviruses, as mentioned above, are included in this group, of which is a member (HIV uses single-stranded RNA as its genetic material). Some double-stranded DNA viruses replicate using reverse transcriptase. The hepatitis B virus is one of these viruses.
    ::反转录入病毒是指使用反转转录出法复制的任何病毒,这种病毒是从RNA模板中形成DNA的。一些反转录入病毒的基因组是由单层RNA制成的;这些病毒使用DNA中间体复制。这一组的其他人有双层DNA制成的基因组;这些病毒在基因组复制过程中使用RNA中间体。如上文所述,反转病毒也属于这一组(艾滋病毒使用单层RNA作为基因材料)。一些双层DNA病毒使用反转转转录酶复制。乙型肝炎病毒是这种病毒之一。

    HIV entry to T cell
    Viral replication using reverse transcription. 1) A virus particle binds to receptors on the outside of the cell membrane. 2) The virus capsid fuses with the cell membrane. 3) The RNA genome of the virus enters the cytoplasm where it is reverse transcribed to DNA. 4) The viral DNA genome is fused into the host genome. 5-7) New virus RNAs are then transcribed from the host genome, transported into the cytoplasm and translated to produce the proteins needed to assemble and export new virus particles.

    Bacteriophages
    ::细菌

    Bacteriophages are viruses that infect . They bind to surface receptor molecules of the bacterial cell and then their genome enters the cell. The protein coat does not enter the bacteria. (See DNA: The Hereditary Material (Advanced) ). Within a short amount of time (just a few minutes in some cases), bacterial polymerase starts translating viral mRNA into protein. These proteins go on to become either new virions within the cell, helper proteins that help assemble new virions, or proteins involved in cell lysis. Viral enzymes aid in the breakdown of the . With some phages , just over twenty minutes after the phage infects the bacterium, over three hundred phages can be assembled and released from the host.
    ::细菌是感染病毒的病毒。它们与细菌细胞的表面受体分子相连,然后它们的基因组进入细胞。蛋白质大衣没有进入细菌(见DNA:遗传材料(高级))。在短短的时间内(有些情况下只有几分钟),细菌聚合酶开始将病毒MRNA转化为蛋白。这些蛋白质要么成为细胞内的新病毒,要么成为帮助组装新病毒的辅助蛋白质,要么成为细胞解析过程中的蛋白质。病毒酶有助于细菌的分解。在细胞感染细菌后短短短的20分钟内,可以聚集并释放出300多个植物。

    Summary
    ::摘要

    • Viruses replicate using the machinery of a host cell.
      ::病毒使用宿主细胞的机器复制。
    • Viral DNA genomes are used directly by the host cell; RNA viruses may replicate using a DNA intermediate.
      ::主机细胞直接使用活性DNA基因组;RNA病毒可使用DNA中间体复制。

    Review
    ::回顾

    1. Compare and contrast DNA virus and RNA virus replication.
      ::比较和对比DNA病毒和RNA病毒复制。
    2. A classmate says that viruses can only infect eukaryotic cells. Do you agree? Explain your answer.
      ::同学说病毒只能感染尿道细胞 你同意吗?