大自然中的生物.docVIP

(j) A cell cycle checkpoint has been identified in this phase. 2. 同一个体不同组织的细胞中, 核仁的大小和数目都有很大的变化, 这种变化和细胞中蛋白质合成的旺盛程度有关。( ) 3. 将同步生长的M期细胞与同步生长的S期细胞融合,除了见到正常的染色体外,还可见到细线状的染色体。( ) 4. 在有丝分裂后期，通过对周期蛋白的遍在蛋白多聚化，介导周期蛋白被蛋白酶体降解，从而退出M期。( ) 5. 核纤层是由核纤层蛋白A、核纤层蛋白B和核纤层蛋白C构成的，其中只有核纤层蛋白A与内核膜相连，核纤层蛋白B和C则与染色质相连。( ) 6. 在细胞周期中，如果纺锤体装配不正常，则被阻止G2期。 7. 结合有核糖体的内质网被称为粗面内质网，脱去核糖体的内质网则称为光面内 质网。( ) 8. 同源异型框是一类同源异型基因表达产物中60个氨基酸的保守序列, 它的突变 可以改变发育的方向。( ) 9. 叶绿体的核酮糖二磷酸羧化酶是由16个亚基组成的聚合体, 其中8个大亚基是核基因编码的。( ) 10. 有丝分裂器中有三种类型的纺锤体微管，其中星微管的可能作用是给核分裂传 递信号。（ ） 11. 在减数分裂过程中,染色体间发生的分子重组是随机发生的。( ) 三、选择题(请将正确答案的代号填入括号，每题1分，共15分) 1. Ethyl alcohol is detoxified in the liver. You would expect alcohol to have which of the following effects on liver cells? （ ） a. Nuclear degeneration b. Growth of the smooth ER c. Increased lysosomes d. Growth of rough ER e. None of the above 2. Which of the following proteins would not be found in the smooth endoplasmic reticulum?（ ） a. Ca2+-pumping enzymes b. cytochrome P450 c. glucose 6-phosphatase d. signal peptidase 3. Which of the following explains why microsomes cant be seen in cells viewed with the electron microscope?（ ） a. They are far too small. b. They are artifacts of homogenization and centrifugation. c. They are transparent to electrons. d. They actually can be seen in electron micrographs of cells. 4. If you compared the proteins in a cis Golgi compartment with those in a trans Golgi compartment, you would find:（ ） a. the proteins in the two compartments are identical. b. the proteins in the cis compartment are glycosylated and contain modified amino acids, whereas those in the trans compartment are not modified. c. the proteins in the cis compartment are glycosylated, whereas those in the trans compartment are glycosylated and contain modified amino acids. d. the proteins of the cis compartment are shorter than those of the trans compartment. 5. Which type of vesicle of the trans Golgi network would be most likely to carry hormones destined for regulated secretion?（