[醫(yī)學(xué)]第十二章翻譯(參考版)
2025-02-24 13:05本頁面
【正文】 and there are special codons for the initiation and termination of peptide synthesis. ? 2. An aminoacyltRNA synthetase catalyzes the addition of a specific amino acid to the acceptor stem of the appropriate tRNA, producing an aminoacyltRNA. ? 3. Ribosomes are the RNAprotein plex. The growing polypeptide chain is attached to a tRNA in the peptidyl (P) site of the ribosome, and the aminoacyltRNA molecule bearing the next amino acid to be added to the nascent polypeptide chain docks in the aminoacyl (A) site. ? 4. Translation begins with the formation of an initiation plex consisting of an initiator tRNA, the mRNA template, the ribosomal subunits, and several initiation factors. In prokaryotes, initiation occurs just downstream of ShineDalgarno sequence. ? 5. The elongation step of translation requires accessory proteins called elongation factors. The three steps of elongation are(1)positioning of the correct aminoacyltRNA in A site, (2)formation of the peptide bond by peptidyl transferase, and (3) translocation of the ribosome by one codon. ? 6. Release factors recognize termination codons and catalyze the termination of protein synthesis and disassembly of the translation plex. ? 7. Many proteins are posttranslationally modified. Some eukaryotic proteins destined for secretion containing Nterminal signals. 使核蛋白體大小亞基保持分離狀態(tài)的蛋白質(zhì)因子是 A、 IF1 B、 IF2 C、 IF3 D、 EF1 E、 EF2 蛋白質(zhì)生物合成中不需要能量的步驟是 A、氨基酰 tRNA合成 B、啟動 C、肽鏈延長 D、轉(zhuǎn)肽 E、終止 密碼 GGC的對應(yīng)反密碼子是 A、 GCC B、 CCG C、 CCC D、 CGC E、 GGC 核蛋白體轉(zhuǎn)肽酶活性，需要的無機(jī)離子是 A、 Ca2+與 K+ B、 Mg2+與 K+ C、 Mg2+與 Na+ D、
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