中山大学2003-2004学年第一学期细胞生物学期中考试试题
一、单选题（本大题15小题．每题1.0分，共15.0分。请从以下每一道考题下面备选答案中选择一个最佳答案，并在答题卡上将相应题号的相应字母所属的方框涂黑。） 第1题
Which one of the following is incorrect for the biogenesis of eukaryotic ribosomes?( )
A 25-50% of the pre-rRNA is degraded B Pre-rRNA binds to ribosomal protein
C Pre-rRNA is cut to form three classes of rRNA D Pre-rRNA is methylated
E The rRNA gene for the 40S subunit is transcribed separately 【正确答案】：E
【本题分数】：1.0分 第2题
The 5S rRNA differs from the other cellular rRNAs in which of the following ways? ( )
A The genes are located outside the nucleolus(核仁). B The genes are transcribed by RNA polymerase III.
C The promoter region of the 5S rRNA gene is internal to the gene. D all of the above 【正确答案】：D
【本题分数】：1.0分 第3题
钙泵的作用主要是( )。 A 降低细胞质中Ca2+的浓度； B 提高细胞质中Ca2+的浓度；
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C 降低内质网中Ca2+的浓度； D 降低线粒体中Ca2+的浓度 【正确答案】：A
【本题分数】：1.0分 第4题
Plant guard cells(保卫细胞) have a higher [C1-] than the outside environment. The most likely explanation for this is( ). A Water leaves the cell by osmosis.
B C1- is diffusing through transmembrane channels. C C1- diffusion is aided by a mobile carrier. D An active transport symport transports C1-/H+. E None of the above 【正确答案】：D
【本题分数】：1.0分 第5题
The hormone glucagons(胰高血糖素) stimulates the breakdown of stored glycogen in liver and muscle cells by the following enzymes. Which is the first enzyme that must be activated? ( ) A Protein kinase A B Phosphorylase kinase C Glycogen phosphorylase D Protein phosphatase
E Protein phosphatase inhibitor-1 【正确答案】：A
【本题分数】：1.0分 第6题
在下列组织中, 紧密连接特别重要的有( ) A Stomach(胃) and kidneys
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