Section outline

  • General

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  • 生物技术生物技术

    What you will learn
    ::你会学到什么

    • The commonly used methods in biotechnology: gene cloning and polymerase chain reaction (PCR)
      ::生物技术中常用的方法:基因克隆和聚合酶链反应(PCR)

    Hands in gloves manipulating a DNA double helix with scissors and tweezers, illustrating biotechnology.

    So how does a scientist work with DNA?
    ::那么科学家如何使用DNA呢?

    It always starts with the sequence. Once the sequence is known, so much more can be done. Specific regions can be isolated, cloned, amplified, and then used to help us.
    ::它总是从序列开始。一旦序列为人所知,就可以做很多事情。特定区域可以被孤立、克隆、放大,然后用来帮助我们。

    Biotechnology Methods
    ::生物技术方法

    Biotechnology is the use of technology to change the genetic makeup of living things for human purposes. Generally, the purpose of biotechnology is to create organisms that are useful to humans or to cure . For example, biotechnology may be used to create crops that resist insect pests or yield more food , or to create new treatments for human diseases.
    ::生物技术是利用技术改变人类生物的基因构成,一般而言,生物技术的目的是创造对人类有用或有助于治愈的有机体。例如,生物技术可以用来制造抗虫害或生产更多食物的作物,或创造治疗人类疾病的新疗法。

    Biotechnology uses a variety of techniques to achieve its aims. Two commonly used techniques are gene cloning and the polymerase chain reaction.
    ::生物技术利用各种技术实现其目标,两种常用技术是基因克隆和聚合酶链反应。

    Gene Cloning
    ::Gene 克隆

    Gene cloning is the process of isolating and making copies of a gene . This is useful for many purposes. For example, gene cloning might be used to isolate and make copies of a normal gene for . Gene cloning involves four steps: isolation, ligation , transformation, and selection. 
    ::基因克隆是分离和复制基因的过程,对许多目的都有用,例如,基因克隆可以用来分离和复制正常基因。基因克隆包括四个步骤:隔离、捆绑、转化和选择。

    1. In isolation, an (called a restriction enzyme) is used to break at a specific base sequence. This is done to isolate a gene.
      ::孤立地说,一种(所谓的限制酶)被用于在特定基数序列中断裂。这是为了分离基因。
    2. During ligation , the enzyme DNA ligase combines the isolated gene with plasmid DNA from . (A plasmid is circular DNA that is not part of a and can replicate independently.) The DNA that results is called .
      ::在捆绑期间,酶DNA链将孤立的基因与来自......(圆形DNA是圆形DNA,不是一种DNA的一部分,可以独立复制。 )结果的DNA被称为 。
    3. In transformation , the recombinant DNA is inserted into a living , usually a bacterial cell. Changing an organism in this way is also called genetic engineering .
      ::在转型中,重组DNA被插入活体细胞,通常是细菌细胞。 以这种方式改变有机体也被称为基因工程。
    4. Selection involves growing transformed bacteria to make sure they have the recombinant DNA. This is a necessary step because transformation is not always successful. Only bacteria that contain the recombinant DNA are selected for further use.
      ::选择涉及生长变异细菌以确保它们拥有重组DNA。 这是必要的一步, 因为转换并不总是成功。 只有含有重组DNA的细菌才被选中供进一步使用 。

     

     

       

    Polymerase Chain Reaction
    ::聚合酶链反应

    The polymerase chain reaction (PCR) makes many copies of a gene or other DNA segment. This might be done in order to make large quantities of a gene for genetic testing. involves three steps: denaturing , annealing , and extension . The three steps are illustrated in the  Figure . They are repeated many times in a cycle to make large quantities of the gene. 
    ::聚合酶链反应(PCR)复制了许多基因或其他DNA部分,这可以是为了将大量基因用于基因测试。这涉及三个步骤:衰落、渗入和扩展。图中说明了这三个步骤。它们在一个周期中重复多次,以产生大量基因。

    1. Denaturing involves heating DNA to break the bonds holding together the two DNA strands. This yields two single strands of DNA.
      ::断裂过程涉及取暖DNA,以打破将两种DNA串联在一起的纽带,产生两条单一的DNA。
    2. Annealing involves cooling the single strands of DNA and mixing them with short DNA segments called primers . Primers have base sequences that are complementary to segments of the single DNA strands. As a result, bonds form between the DNA strands and primers.
      ::Annaling涉及冷却单一的DNA片段,并将其与称为基质的短DNA片段混为一谈。 基级序列与单一DNA片段相辅相成。 因此,DNA片段和基质之间形成了联系。
    3. Extension occurs when an enzyme ( Taq polymerase or Taq DNA polymerase) adds nucleotides to the primers. This produces new DNA molecules, each incorporating one of the original DNA strands.
      ::当酶(Taq聚合酶或Taq DNA聚合酶)在基质中添加核素时,就会发生延展,从而产生新的DNA分子,每个分子都含有原有的DNA链。
    The PCR process showing denaturing, annealing, and extension steps.
    The Polymerase Chain Reaction. The polymerase chain reaction involves three steps. High temperatures are needed for the process to work. The enzyme Taq polymerase is used in step 3 because it can withstand high temperatures.

     

     

     

     

    DID YOU KNOW?

    Cloning is not always successful. Most of the time, this cloning process does not result in a healthy adult , and the process has to be repeated many times until it works. The high failure rate of this process is one reason that human cloning is prohibited in many countries. 
    ::克隆并不总是成功的。 大部分时间,这种克隆过程不会导致一个健康的成年人,而且这一过程必须重复多次,直到起作用为止。 这一过程的高失败率是许多国家禁止人的克隆的原因之一。

     

     

    Summary
    ::摘要

    • Biotechnology is the use of technology to change the genetic makeup of living things for human purposes.
      ::生物技术是利用技术改变人类生物的遗传构成。
    • Gene cloning is the process of isolating and making copies of a DNA segment such as a gene.
      ::基因克隆是分离和复制基因等DNA部分的过程。
    • The polymerase chain reaction makes many copies of a gene or other DNA segment.
      ::聚合酶链反应产生许多基因或其他DNA元件的副本。

    Review
    ::回顾

    1. Define biotechnology.
      ::界定生物技术。
    2. What is recombinant DNA?
      ::什么是重组DNA?
    3. Identify the steps of gene cloning.
      ::确定基因克隆的步骤。
    4. What is the purpose of the polymerase chain reaction?
      ::聚合酶链反应的目的是什么?
    5. Describe the three steps of PCR.
      ::描述PCR的三个步骤。