武漢大學(xué)分子生物學(xué)全部課程3-在線瀏覽
2025-03-13 02:40本頁(yè)面
【正文】 topoisomerase? 2. The functional difference of the two types of topoisomerases? 3. The working mechanism of topoisomerase (See the animation for detail) DNA TOPOLOGY (4) RNA STRUCTURE RNA STRUCTURE (1) RNA contains ribose and uracil and is usually singlestranded Biological roles of RNA 1. RNA is the geic material of some viruses 2. RNA functions as the intermediate (mRNA) between the gene and the proteinsynthesizing machinery. 3. RNA functions as an adaptor (tRNA) between the codons in the mRNA and amino acids. 4. RNA serves as a regulatory molecule, which through sequence plementarity binds to, and interferes with the translation of certain mRNAs. 5. Some RNAs are enzymes that catalyze essential reactions in the cell (RNase P ribozyme, large rRNA, selfsplicing introns, etc). Structure (1): RNA chains fold back on themselves to form local regions of double helix similar to Aform DNA RNA STRUCTURE (2) hairpin bulge loop RNA helix are the basepaired segments between short stretches of plementary sequences, which adopt one of the various stemloop structures Some tetraloop sequence can enhance the stability of the RNA helical structures For example, UUCG loop is unexpectedly stable due to the special basestacking in the loop Pseudoknots are plex structure resulted from base pairing of discontiguous RNA segments Figure 632 Pseudoknot. NonWatsonCrick G:U base pairs represent additional regular base pairing in RNA, which enriched the capacity for selfplementarity Figure 633 G:U base pair The double helical structure of RNA resembles the Aform structure of DNA. The minor groove is wide and shallow, but offers little sequencespecific information. The major g
教學(xué)課件相關(guān)推薦
鄂ICP備17016276號(hào)-1