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所在平台: Udemy |
课程主页: https://www.udemy.com/course/rna-structure-detailed-concept/
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本课程“RNA结构详细概念”将深入探讨RNA的分子结构。 RNA（核糖核酸）是由核糖核苷酸组成，通过3',5'-磷酸二酯键连接而成。虽然RNA与DNA在结构上有相似之处，但RNA具有其独特的差异： * **戊糖：** RNA中的糖是核糖，而DNA是脱氧核糖。 * **嘧啶碱基：** RNA含有尿嘧啶（Uracil）取代DNA中的胸腺嘧啶（Thymine）。 * **单链结构：** RNA通常是单链多核苷酸。然而，单链可能会在某些区域折叠形成双链结构，如果互补碱基对靠近。 * **Chargaff法则不适用：** 由于其单链的性质，RNA的嘌呤和嘧啶含量之间没有特定的比例关系，例如鸟嘌呤（Guanine）含量不等于胞嘧啶（Cytosine）含量。 * **对碱性水解的敏感性：** RNA能被碱性物质水解成2,3-环状二酯，这是由于其2位羟基（-OH）的存在。DNA由于缺乏此基团，则不易被碱性水解。 * **Orcinol 颜色反应：** 由于核糖的存在，RNA可以通过Orcinol颜色反应在组织学上被识别。 课程还将介绍RNA的类型，包括信使RNA（mRNA）、核糖体RNA（rRNA）和转运RNA（tRNA）。 RNA，即核糖核酸，是由核糖、磷酸和腺嘌呤、鸟嘌呤、胞嘧啶、尿嘧啶等碱基组成的核苷酸聚合物。它在基因表达中扮演着关键角色，作为DNA编码的遗传信息与蛋白质之间的媒介。RNA的结构与DNA非常相似，主要区别在于RNA的核糖糖分子在2位上多了一个羟基（-OH）基团。 更多详细内容可在课程的演示文稿中找到。
RNA is a polymer of ribonucleotides held together by 3 ,5 -phosphodiester bridges.Although RNA has certain similarities with DNA structure ,they have several specific differences.1.Pentose The sugar :in RNA is ribose in contrast to deoxyribose in DNA. 2.pyrimidine: RNA contains the pyrimidine uracil in place of thymine 3.Single strand: RNA is usually a single stranded polynucleotide. How ever, this strand may fold at certain places to give a double stranded structure, if complementary base pairs are in close proximity.4.chargaff"srule - not obeyed: Due to the single- stranded nature, there is no specific relation between purine and pyrimidine contents.Thus the guanine contents is not equal to cytosine(as is the case in DNA)5.Susceptability to alkali hydrolysis: Alkali can hydrolyze RNA to 2,3-cyclic diesters.This is possible due to the presence of a hydroxyl group at 2 position.DNA cannot be subjected to alkali hydrolysis due to lack of this group.6.Orcinol color reaction:RNAs can be histologically identified by orcinol color reaction due to the presence of ribose.Types of RNA: mRNA, rRNA and tRNARNA or ribonucleic acid is a polymer of nucleotides that is made up of a ribose sugar, a phosphate, and bases such as adenine, guanine, cytosine, and uracil. It plays a crucial role in gene expression by acting as the intermediate between the genetic information encoded by DNA and protein RNA has a structure very similar to that of DNA. The key difference in RNA structure is that the ribose sugar in RNA possesses a hydroxyl (-OH) group that is absent in DNA.and much more you can find in session presentations.
