本题目来源于试卷: Unity and Diversity A.2 Nucleic Acids，类别为 IB生物学
[单选题]
The diagram below sh 6ptavyfnelu-qt )/; (0ry 6yh)fc nwyj2o(y jv 2tc 6g:,vb7rows pre-mRNA and three mature mRNA transcripts where the int vtvnr,( 2yyg2:6 o c7)cjfb wjrons have been removed.
What is an advantage of the above process?
A. The rate of transcription increases.
B. Different polypeptides can be produced from one pre-mRNA transcript.
C. Translation occurs immediately after transcription.
D. Prokaryotes can produce a variety of proteins from one section of DNA.
参考答案: B
本题详细解析:
The above process shows the splicing of mRNA in which introno+*bhxp 1ic wg85z w9avfv yn). x/e9ms are removed and exons are joined together in different arrangements. The advantage of mRNA splicing is that the number of different polypeptides that can be produced by one segment of DNA is increased. mRNA splicing only occurs in eukaryotes.Splicing does not increase the rate of transcription as it occurs after transcription is complete (Choice A).In eukaryotes, translation takes place after post-transcrinxb9 xwv /i. ve8a5 h)zcmp o1+wf9*ygptional modifications are complete which requires several steps, so translation does not occur immediately after transcription (Choice C).Splicing of mRNA does not take place in prokaryotes because there are no introns in prokaryotic DNA (Choice D).
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