章节大纲

  • 常规

    全部折叠 展开全部

  • RNA结构 -- -- 高级

    Model of the small 30S subunit of the ribosome molecule.

    Protein or RNA molecule?
    ::蛋白质还是RNA分子?

    Actually both. This is the model of the 30S subunit of the molecule. It is made of both and . The RNA in this ribosome, though, has protein-like properties. RNAs are able to fold back onto themselves, folding into three-dimensional structures with functional properties. Sometimes these are enzymatic properties, such as those found in the ribosome.
    ::事实上两者都有。 这是分子的 30 S 子单位的模型。 它由两者组成 。 但是, 在这种核糖核酸中, RNA 具有蛋白质相似的特性 。 RNA 可以折叠到自己身上, 折叠到三维结构中, 并具有功能性 。 有时这些是酶特性, 比如在核糖核酸中发现的特性 。

    RNA Structure
    ::RNA 结构

    RNA structure differs from structure in three specific ways. Both are and made out of nucleotides ; however, RNA is single stranded while DNA is double stranded. RNA nucleotides, like those from DNA, have three parts: a 5-carbon sugar, a phosphate group and a base. RNA contains the 5-carbon sugar ribose , whereas in DNA, the sugar is deoxyribose. The difference between ribose and deoxyribose is the lack of a hydroxyl group attached to the pentose ring in the 2' position of deoxyribose.
    ::RNA结构在三种具体方式上与结构不同:两者都是用核糖核酸制成的;然而,RNA都是单独受困的,而DNA是双重受困的。RNA核糖核酸与DNA一样,有三部分:5碳糖、磷酸盐组和基底。RNA含有5碳糖肋骨,而在DNA中,糖是脱氧核糖。肋骨和脱氧核糖的区别在于在2的脱氧核糖基位置上缺乏附在钢管环上的氢氧基。

    Though both RNA and DNA contain the nitrogenous bases adenine, guanine and cytosine, RNA contains the nitrogenous base uracil instead of thymine. Uracil pairs with adenine in RNA, just as thymine pairs with adenine in DNA. Uracil and thymine have very similar structures; uracil is an unmethylated form of thymine.
    ::虽然RNA和DNA都含有氮基、谷氨和细胞素,但RNA含有氮基,而不是甲状腺。 RNA中带有甲状腺的乌拉西人配有甲状腺的乌拉西人与甲状腺的甲状腺对齐,就像DNA中含有甲状腺的甲状腺对齐一样。 乌拉西人和甲状腺的结构非常相似;乌拉西人是一种未甲基的甲状甲状腺。

    The nucleotide sequence of RNA, which is complementary to the DNA sequence, allows RNA to encode genetic information. RNA though carries the genetic information of just one gene . Hence, compared to DNA, RNA molecules are relatively small.
    ::RNA的核核酸序列是对DNA序列的补充,它使得RNA能够编码遗传信息。RNA虽然只携带一个基因的遗传信息,但只携带一个基因的遗传信息。 因此,与DNA相比,RNA分子相对较少。

    A comparison of RNA and DNA is shown in Table  .
    ::RNA和DNA的比较见表。

      RNA DNA
      single stranded double stranded
    Specific Base contains uracil contains thymine
    Sugar ribose deoxyribose
    Size relatively small big (chromosomes)
    Location moves to cytoplasm stays in
    Types 3 types: mRNA, tRNA , rRNA generally 1 type

    RNA Activity
    ::RNA 活动

    Analysis of RNAs has revealed that they are highly structured. Unlike DNA, most RNAs, though single-stranded, do form specific secondary structures. Like proteins, the folded structure of the RNA is specific and gives the RNA functional properties. Some RNAs contain self-complementary sequences that allow parts of the RNA to fold and pair with itself to form double helices. RNA nucleotides base-pair like DNA nucleotides, however in DNA, this base-pairing is necessary to form the double helix structure uniform to all DNA. In RNA, the base pairs would be A-U and G-C pairings. The in RNA is unique to each molecule of RNA and results in a three-dimensional structure that gives each molecule functional properties. Unlike DNA, their structures do not consist of long double helices but rather collections of short helices combined into a functional molecule. Because of the structure of RNA, the RNA molecule can achieve biochemical catalysis, similar to that of . For instance, the structure of the ribosome allows peptide bond formation during . The active site of the ribosome is composed entirely of RNA.
    ::与DNA不同的是,大多数RNA(尽管是单弦的)的确形成特定的二级结构。像蛋白质一样,RNA(RNA)的折叠结构是具体的,并赋予RNA功能性。有些RNA(RNA)含有自补充序列,使RNA的一部分能够折叠并配成双向性螺旋。RNA(核糖核酸)基底(核酸)与DNA(核糖核酸)相似,但是在DNA中,这种基底涂层对于形成与所有DNA一致的双螺旋结构是必要的。在RNA(RNA)中,基配对将是A-U和G-C配对。RNA(RNA)中每个分子都是独特的,并产生三维结构,使每个分子的功能性能性能。与DNA不同的是,它们的结构不是长期的双向的,而是将短期的螺旋结合成一个功能性分子。由于RNA的结构,RNA(RNA)分子可以实现与所有DNA(DNA)相类似的生物化学催化解。例如,正质关系组成的构造结构完全允许在RNA(RIMO)形成)中。

    Summary
    ::摘要

    • RNA is a single-stranded nucleic acid.
      ::RNA是一种单柱核核酸。
    • RNA contains the nitrogenous base uracil.
      ::RNA含有氮基聚氨酯
    • RNA can fold into three-dimensional structures with functional properties.
      ::RNA可以折叠成三维结构,具有功能特性。

    Review
    ::回顾

    1. Describe the differences between DNA and RNA.
      ::说明DNA和RNA之间的区别。
    2. How does RNA have functional properties?
      ::RNA是如何具有功能特性的?
    3. What is the structural difference between uracil and thymine?
      ::乌拉基尔和甲状腺之间的结构区别是什么?