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]
Which statement highlights the impor1tznm6 ,l/ 1ie c44ptqml tw3cjr1. ca3fh)wktance of nuclefde:dm. uj;0j osomes in DNA supercoiling ?
A. To fit the length of DNA into the nucleus
B. To access specific DNA sequences
C. To form a circular chromosome
D. To hold the information needed for coding amino acids
参考答案: A
本题详细解析:
A nucleosome helps to supercoil the DNA in order to packnycge zpg*1d6 m6de,):nr:vlcb *d0aage the DNA into a more condensed and compact structure. With this packaging, a length of DNA, totalling 2m, would be able to fit into the nucleus.Even though the DNA is packed into the nucleus, nucleosomes can still allow access to specific DNA sequencese ):ylcc 1g ba:06*rvded6dn gnz*p,m for the transcription process (choice B). DNA can be accessed with or without the nucleosomes present.The circular chromosome found in bacterial cells is shorter than the chromosomes of eukaryotic cells so they do not require any DNA packaging, hence the absence of nucleosomes (choice C).DNA acts as a template for RNA transcription, which then is used to code for amino acids. A nucleosome is used to supercoil the DNA and does not hold the information to code for amino acids (choice D).
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