Two distinct classes of aminoacyl-tRNA synthetases exist. What might explain this? Please choose the correct answer from the following choices,单项选择题

A

One class contains modified amino acids that specifically bind the modified bases of some tRNAs.

B

Recognition sites on both faces of tRNA may be required to distinguish 20 different tRNAs.

C

Two classes are needed because tRNAs can be both L-shaped or cloverleaf shaped.

D

One class of aminoacyl-tRNA synthetases is used for hydrophobic amino acids while the other class is used for the polar amino acids.

E

None of the above

登录即可查看完整答案

我们收录了全球超50000道真实原题与详细解析,现在登录,立即获得答案。

类似问题

An enzyme known as ___________ attaches an amino acid to the                        of a tRNA, thereby producing …………………

Assume a mutation in the CCA arm of tRNAThr occurs that reduces the flexibility of this region of the molecule but still allows the 3′ end of the tRNA to enter the aminoacyl-tRNA synthetase activation site. Which of the following is the most likely outcome?

In the original publication of the 1QF6 structure (Sankaranarayanan et al., 1999), the authors were able to clarify the secondary and tertiary structure of the bacterial threonyl-tRNA synthetase, and to show that it folds into multiple domains (i.e. independently-folding regions).   The image below from the article shows the 'domain structure' of the enzyme, while also emphasizing its secondary structure (with cylinders representing alpha-helices and thin ribbons representing beta-strands):     (You may notice that the image resolution is somewhat low. This sometimes happens with older publications such as this one, which were not originally released in digital format and were scanned later.)   To create successful conditions for generating the 3D 1QF6 structure, the researchers note that they provided the enzyme with the appropriate tRNA as well as ATP, and that the final crystal structure contained AMP (but not ATP).    Thinking back to the information provided about this enzyme, which one of the following best explains why the nucleotide in the 1QF6 structure has two fewer phosphates than the nucleotide that was originally provided to the enzyme?    

Question at position 20 One disadvantage of the functional structure is that:career paths and professional development are limiteddual reporting relationships blur lines of authoritythe CEO cannot coordinate and control the efforts of functional-level employeescommunication and coordination are difficult among organizational functions

更多留学生实用工具

加入我们，立即解锁 海量真题 与 独家解析，让复习快人一步！