本题目来源于试卷: Form and Function B.4 Organelles & Compartmentalization，类别为 IB生物学
[单选题]
Which of the following sr e rzg+;;2tq/nfm yghag+ c+5ubston469 kjsk ,req-gbd7ances cannot pass through the pores of the nuclear membrane,4 qo g9j7dek-6 knsbr?
A. mRNA
B. DNA
C. ribosomal proteins
D. ions
参考答案: B
本题详细解析:
The main role of the nuclear envelope is to compartmentalise the DNA from the cytoplasm in eukaryotic cells. DNA is a large complex molecule which is too large to pass through the nuclear pores. Therefore Choice B is correct. The pores in the nuclear envelope regulate the movement of molecules between the nucleus and cytosol. Nuclear pores allow small molecules and ions (Choice D) to diffuse through them. Many proteins (Choice C) required for transcription and DNA replication are made in the cytosol and selectively imported into the nucleus. Molecules, such as mRNA (Choice A) and tRNA are made in the nucleus and exported into the cytosol. Much of this transport across the membrane is selective, for example, mRNA can only be exported once it has been formed into mature RNA through the process of splicing.
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