【判断题】从 结合类型来看,硅是典型的 原子 晶体, NaCl是 分子 晶体。
【单选题】大隐静脉高位结扎、曲张静脉剥脱术后的护理,错误的一项是( )
【多选题】Why do we think that the ribosome is a ribozyme?
A.
The rRNAs are folded into highly compact, precise three-dimensional structures that form the core of the ribosome. In contrast to the central positioning of the rRNAs, the ribosomal proteins are generally located on the surface, where they fill the gaps and crevices of the folded RN
B.
The main role of the ribosomal proteins seems to be to help fold and stabilize the RNA core, while permitting the changes in rRNA conformation that are necessary for this RNA to catalyze efficient protein synthesis.
C.
Not only are the three tRNA-binding sites (the A, P, and E sites) on the ribosome formed primarily by the rRNAs, but the catalytic site for peptide bond formation is formed by the 23S rRNA of the large subunit; the nearest ribosomal protein is located too far away to make contact with the incoming amino acid or with the growing polypeptide chain.
D.
The catalytic site in this RNA—a peptidyl transferase—is similar in many respects to that found in some protein enzymes: it is a highly structured pocket that precisely orients the two reactants—the elongating polypeptide and the amino acid carried by the incoming tRNA—thereby greatly increasing the likelihood of a productive reaction.
【单选题】Recently, I bought a new apartment(公寓), _______ was high.
【简答题】where does it's name come from? Coronaviruses are large group of _____, they consist of core of genetic material surrounded by an envelope of proteins spikes. This gives it the _____ of crown. Crown i...
【单选题】配电所一般为户内型,单台变压器容量不宜超过( ),一般为2台,进线两回。
【判断题】对于临时来访的来宾,秘书也应该“有求必应”。
【单选题】以下对于大隐静脉高位结扎、曲张静脉剥脱术后的护理中不正确的是
【简答题】配电所一般为户内型,单台变压器容量不宜超过( ),一般为2台,进线两回。