章节大纲

  • 常规

    全部折叠 展开全部

  • RNA 类型 - 高级

    RNA structure

    How does the information move from the nucleus, where the DNA is located, to the cytoplasm, where the ribosomes are?
    ::信息是如何从DNA所在的核 到细胞托盘 和骨质细胞的呢?

    , the other , that's how. Specifically mRNA or messenger RNA . RNA, the middle player in the . This image is an abstract representation of transfer RNA , which brings the amino acid to the . Without tRNA , mRNA, and rRNA, cannot be made.
    ::。 具体来说, mRNA 或 送信 RNA 。 RNA , 中间玩家 。 此图像是传输 RNA 的抽象表示, 将氨基酸带到 NA 。 没有 tRNA 、 mRNA 和 RRNA , 就无法实现 。

    Types of RNAs
    ::RNA 类型

    So what is the role of? We know that RNA is the middle player in the central dogma of molecular biology , but is that all it does?
    ::我们知道RNA是分子生物学核心教条的中间角色,但这就是它的作用吗?

    There are three types of RNA involved in : messenger RNA (mRNA), transfer RNA (tRNA), and ribisomal RNA (rRNA). All three of these nucleic acids work together to produce a protein. The mRNA takes the genetic instructions from the to the cytoplasm , where the ribosomes are located. Ribosomes are the where the proteins are made. The ribosomes themselves are made out of rRNA and other proteins. The mRNA binds to the ribosome, bringing the genetic instructions to order the amino acids to the site of protein synthesis. Finally, the tRNA brings the correct amino acid to the ribosome ( Figure  and Figure  ). In mRNA, the four nucleotides (A, C, G, and U) are arranged into codons of three bases each. Each codon encodes for a specific amino acid, except for the stop codons , which terminate protein synthesis. tRNA, which has a specific “3-leaf clover structure,” contains a three base region called the anticodon , which can base pair to the corresponding three-base codon region on mRNA. More will be discussed on these processes in the Protein Synthesis: The (Advanced) and Protein Synthesis: (Advanced) concepts.
    ::RNA有三种类型的RNA:发送RNA(mRNA),传输RNA(tRNA)和Ripisomal RNA(rRNA),所有三种核酸都合在一起生产蛋白质。MRNA将基因指令从骨质素所在的细胞图拉斯姆传到骨质素所在的细胞图拉斯姆。Riboomes是产生蛋白的地方。肋骨是由RNA(mRNA)和其他蛋白质制成的。MRNA(tRNA)与肋骨结合,将氨酸的基因指示带到蛋白质合成场所。最后,TRNA将正确的氨酸带给蛋白质合成场所(Figre和图图)。MRNA将基因指令从骨质素所在的细胞图解到骨质素所在的细胞细胞链,4个核糖素(A、C、G和U)被安排成3个基。每种蛋白质合成氨酸的cod编码,但停止合成蛋白质合成的codoncod(rNA)除外。 反RNA(RONA),在3ABOD-CA 区域将一个更具体的根基结构上讨论这些根基:3-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-Con-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-B-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-B-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-

    Three RNAs
    ::三个RNA

    Remember that proteins are made out of amino acids. How does the information in the gene get converted from the language of nucleotides to the language of amino acids? The process is called translation . The amino acids are placed in a specific order during translation. The order is specified by the codons in the mRNA, which is produced during . As the mRNA sequence is based on the gene sequence in the , the order of amino acids that makes the protein is based on the gene sequence as well.
    ::记住蛋白质是用氨基酸制成的。 基因中的信息是如何从核糖核酸语言转换成氨基酸语言的? 这一过程被称为翻译。 氨基酸在翻译过程中被置于特定顺序中。 该顺序由MRNA的codon 指定, 其生产时间为 。 由于 mRNA 序列以该基因序列为基础, 导致蛋白质的氨基酸顺序也以基因序列为基础 。

    The three RNAs involved in protein synthesis are summarized here:
    ::以下概述了参与蛋白质合成的三个RNA:

    1. mRNA (messenger RNA): Produced during transcription. Carries the genetic instructions of a gene from the nucleus to the ribosome in the cytoplasm.
      ::mRNA(发信人RNA):在转录过程中制作的。将基因的遗传指令从核到细胞托盘的血清。
    2. rRNA (ribosomal RNA): Together with proteins, composes the ribosome, the organelles that are the site of protein synthesis.
      ::rRNA(RNA):与蛋白质一道,组成了作为蛋白质合成场所的有机体的肋骨。
    3. tRNA (transfer RNA): Brings the correct amino acid to the ribosome during translation.
      ::TRNA(转移RNA):在翻译过程中将正确的氨基酸引入肋骨。
    lesson content
    2-Dimensional tRNA structure depicting the 3-leaf clover structure. The D arm (D) is one stem ending in a loop. The anticodon arm (A) is a second stem whose loop contains the anticodon on the bottom of the tRNA. The T arm (T) is the third stem opposite the D arm.
    lesson content
    3-Dimensional representation of a tRNA. Coloring: CCA tail in orange, Acceptor stem in purple, D arm in red, Anticodon arm in blue with Anticodon in black, and T arm in green. The acceptor stem is made by the base pairing of the 5'-terminal nucleotide with the 3'-terminal nucleotide. The CCA tail is a CCA sequence at the 3' end of the tRNA molecule, used to attach the amino acid. This sequence is important for the recognition of tRNA by enzymes critical in translation.

    Other RNAs
    ::其他RNA

    Small interfering RNA (siRNA), microRNA (miRNA) and small nuclear RNA (snRNA) are other types of RNA. siRNA and miRNA are revolutionizing molecular biology , developmental biology, and even medicine. The 2006 in Physiology and Medicine was awarded to Dr. Andrew Fire and Dr. Craig Mello for their discovery of siRNA, which is a type of double-stranded RNA that inhibits at the mRNA level. siRNAs are usually 20-25 nucleotides in length. Specifically, siRNA acts on processed mRNA by targeting it for degradation. siRNA is responsible for RNA interference (RNAi) where it interferes with the expression of specific genes with nucleotide sequences complementary to the siRNA. RNAi has a natural role in that it is used by plants in defense against plant viral RNAs.
    ::小型干扰RNA(SiRNA)、微型RNA(MIRNA)和小型核子RNA(SnRNA)是其他类型的RNA。 SiRNA和MIRNA正在对分子生物学、发育生物学、甚至医学进行革命。2006年,在生理学和医学方面,Andrew Fire博士和Craig Mello博士被授予SiRNA(2006年),因为他们发现了SiRNA,这是一种双层RNA,在 mRNA水平上受到抑制。SiRNA通常有20至25个核核核素长度。具体来说,SiRNA对加工的MRNA采取行动,将它作为降解目标。SiRNA干预了RNA(RNAi),干扰了与SiRNA相补充的核子序列特定基因的表达。RNAiRNA具有自然作用,因为植物在防控植物病毒RNA中使用它。

    lesson content
    Mediating RNA interference. siRNAs are transcribed and then processed by the enzyme Dicer, an endoribonuclease in the RNase III family. This enzyme cleaves double-stranded RNA and pre-microRNA into short double-stranded siRNA RNA fragments. These can then bind to mRNA and target the mRNA for degradation.

    miRNAs are also involved in the regulation of gene expression. They are transcribed but not translated into proteins. snRNAs are found within the nucleus of eukaryotic cells . They are involved in a variety of important processes such as RNA splicing (removal of introns), and regulation of , proteins involved in turning on or off genes.
    ::MIRNAs也参与基因表达方式的调节,它们被转录,但没有被转化成蛋白质。 SnRNAs出现在尿道细胞核心中,它们参与各种重要过程,如RNA的切除(移走开子)和对转基因或脱基因的蛋白质的调节。

    Summary
    ::摘要

    • There are three types of RNA: mRNA, tRNA, and rRNA.
      ::RNA有三种类型:MRNA、tRNA和RRNA。
    • mRNA is the intermediary between the nucleus, where the DNA lives, and the cytoplasm, where proteins are made.
      ::mRNA是DNA所居住的核与蛋白质制造的细胞托巴拉斯姆之间的中间体。
    • rRNA and tRNA are involved in protein synthesis.
      ::RRNA和tRNA参与蛋白质合成。
    • Additional RNAs are involved in gene regulation and mRNA degradation.
      ::更多的RNA涉及基因调节和MRNA降解。

    Review
    ::回顾

    1. What are the three main types of RNA? Describe their roles.
      ::RNA的三种主要类型是什么? 说明它们的作用。
    2. Describe the structure and role of siRNAs.
      ::说明SiRNA的结构和作用。
    3. Define a codon.
      ::定义一个codon。