一、填空题

1. 细胞中水对于维持细胞温度的相对稳定具有重要作用，其原因是                              。

2. 纤粘连蛋白与细胞结合的结构域具有特征性的三肽结构，简称RGD 序列，代表的三个氨基酸是∶                   。

3. _                    _ is an intracellular protein that binds calcium and activates enzymes.

4.A substance that fits into a specific binding site on the surface of a  protein molecule is called a __                .

5.  Two products of phospholipase C activity that serve as second messengers are _                and              .

二、判断题

1. Ⅱ型内含子的剪接与核剪接机理相似, 都要形成剪接体和套索结构。(      )

2.  5SrRNA是由RNA聚合酶Ⅱ转录的, 它使用的是内部启动子。(     )

3.  The surface area/volume ratio is generally greater for a prokaryotic cell

than for a eukaryotic cell.（      ）

4.  The ribosomes found in the mitochondria of your musde cells are more like

those of the bacteria in your intestine than they are like the ribosomes

in the cytosol of your musde cells.（      ）

5. Facilitated diffusion of a cation occurs only from a compartment of higher concentration to a compartment of lower concentration.(     )

三、选择题

1. The distribution of K+ across an artificial membrane was measured, and the concentrations were found to be equal on both sides. Which of the following statements is true about the distribution of K+?(     )

a.K+ must be at equilibrium across the cell membrane

b.K+ cannot be at equilibrium across the membrane

c.There cannot be a membrane potential under these conditions

More information is needed to determine whether K+ is at

equilibrium

2.Which mutant form of ras is likely to cause malignancy?(     )

a.ras that cannot hydrolyze GTP      b.ras that cannot bind to GTP

c.ras that cannot bind to Grb2 or Sos  d.ras that cannot bind to Raf

3.  The hormone glucagon 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

4.  A cancer-causing gene makes G protein permanently bind to GTP, this results in(     ).

a. Continual production of cAMP.    b. Continual production of GDP.

c. Inhibition of cGMP production.    d. Inhibition of adenylyl cyclase.

e. None of the above

5.  Which one of the following is not part of a prokaryotic ribosome?(  )

a. A 30S subunit consisting of 16S rRNA

b. A 50S subunit consisting of 23S and 5S rRNA

c. A 30S subunit consisting of 21 proteins

d. A 40S subunit consisting of 18S rRNA

e. None of the above

四、简答题

1.  1981年，Thomas Cech和他的同事在世界上首次发现核酶，并获得了支持这一发现的实验证据。从他们的发现中你有何感想？

2.  为什么说水是细胞中优良的热缓冲体系？

五、问答题

1. 生物膜是怎样合成的?可能的机理是什么?

2. 微管组装的基本过程怎样?