武汉大学生命科学学院
2006-2007 学年度第二学期期末考试
《病毒学》A 试卷
姓名
学号
专业
得分
一．判断对错题，正确的选项请在括号中填写“╋”错误的选项填写“━”
（60*1=
60 分）
Are the following statements true or false?
（ ）1. Ribosomal frameshifting allows viruses to produce a polyprotein from an
mRNA.
（ ）2. Ribosomal frameshifting allows viruses to produce varying amounts of
different proteins from an mRNA.
（ ）3. Suppression of termination codons allows some viruses to produce multiple
proteins from a polycistronic mRNA.
（ ）4. Viruses with non-segmented minus-sense genomes produce monocistronic
mRNAs.
（ ） 5. Viruses with minus-sense genomes always contain a virus-specific
transcriptase/replicase within the virus nucleocapsid.
（ ）6. Viruses with non-segmented miuns-sense genomes are translated to produce
a single long polyprotein.
（ ）7. Retrovirused are the only RNA viruses whose genomes are transcribed by
cellular RNA polymersase.
（ ）8. Hepadnavirus and Caulimovirus genomes contain a number of overlapping
reading frames.
（ ）9. Treatment of virus infections with drugs is cost effective compared with
vaccination.
（ ）10. Any of the stages of virus replication can be potential target for antiviral
chemotherapy.
（ ）11. The majority of antiviral drugs in use are nucleoside/nucleotide analogues.
（ ）12. Ribavirin is only active against influenza virus.
（ ）13. Viruses may become resistant ot antiviral drugs.
（ ）14. Subunit vaccines are generally the most effective and least expensive virus
vaccines.
（ ）15. The hepatitis B virus vaccine currently in use is produced by genetic
engineering.
（ ）16. Inactivated virus vaccines are sometimes not as effective as 'live' virus
vaccines because they fail to stimulate mucosal and cell-mediated
immunity.
（ ）17. The majority of successful virus vaccines are currently based on attenuated
viruses.
（ ）18. Retroviruses have been successfully used as vectors for gene therapy.
（ ）19. Most disease states are multi-factorial.
（ ）20. Inflammation, fever, headaches and skin rashes are frequently not caused by
virus replication, but the immune response to virus infection.
（ ）21. The vast majority of virus infections do not result in disease.
Viruse with plus-sense RNA genome (true or false?):
（ ）22. are largely independent of cellular mechanisms for control of gene
expression.
（ ）23. are always expressed as subgenomic RNAs.
（ ）24. are always translated to produce a single long polyprotein.
（ ）25. can produce varying ratios of the polypeptides they encode by mechanisms
such as alternative cleavages of polyproteins and variable translation
efficiency of subgenomic RNAs.
Transformed cells may display(true or false?)
（ ）26. loss of anchorage dependence.
（ ）27. loss of contact inhibition.
（ ）28. colony formation in semi-solid media.
（ ）29. Decreased requirements for growth factors.
（ ）30. increased requirements for growth factors.
（ ）31. Increased expression of p53.
PrPc(true or false?)
（ ）32. is a 254 amino acid protein.
（ ）33. is encoded by a cellular gene.
（ ）34. is converted by PrPSc to a protease-resistant form.
（ ）35. consists of 30percent alpha-helix and 43 percent beta-sheet.
（ ）36. is resistant to short-wave ultraviolet radiation and to ionizing radiation.
（ ）37. Populations of virus genomes consisting of mixtures of molecular variants
are known as quasispecies.
（ ） 38. Site-specific molecular biological methods are commonly used to
mutagenize virus genomes.
About retroviruses (true or false?):
（ ） 39. Reverse transcriptase is also expressed by hepadnaviruses and
caulimoviruses.
（ ） 40. Are the only RNA viruses whose genome is produced by cellular
transcriptional machinery.
（ ）41. Are the only plus-sense RNA viruses whose genome does not serve directly
as mRNA immediately after infection.
（ ）42. Have low mutation rates, due to the high fidelity of reverse transcriptase
（ ）43. Have a high rate of recombination, due to reverse transcription.
Are the following statements true or false?
（ ）44. Virus penetration of cells is an energy-dependent process.
（ ）45. influenza haemagglutinin is a virus fusion protein.
（ ）46. Uncoating only occurs in the nucleus of the host cell.
（ ）47. The product of uncoating is usually a complex of nucleic acids and virus
proteins.
（ ）48. Nucleoproteins associated with virus genomes are responsible for cell
penetration.
（ ）49. Virus receptor molecules are always proteins.
（ ）50. Most viruses have more than one receptor molecular.
（ ）51. No known plant virus used a cellular receptor.
（ ）52. Sialic acid is the influenza virus receptor.
（ ）53. The expression of receptors on the surface of cells is the major factor which
determines the tropism of viruses.
（ ）54. Adenoviruses encode their own DNA polymerase.
（ ）55. Poxviruses encode their own DNA polymerase and are independent of
cellular enzymes for genome replication.
（ ）56. Reovirus genomes are transcribed by a virus enzyme present in the particle.
（ ）57. All RNA virus genomes are replicated in the nucleus of the host cell.
（ ）58. Retrovirus genomes are transcribed by cellular RNA polymerase.
（ ）59. Reovirus transcription occurs inside virus core particles.
（ ）60. Segmented virus genomes are usually transcribed to produce polycistronic
mRNAs.
二．问答题
1．逆转录病毒与 DNA 肿瘤病毒都可以引起细胞转化，请比较两类病毒引起细
胞转化的机制有何不同。（10 分）
能够转化细胞的逆转录病毒分为三类：转换、顺式作用 和反式作用。
（1）转换：来自复制缺陷、急性转化的逆转录病毒所产生的原癌蛋白都是融合
蛋白，包含有源于病毒基因的附加序列，一般病毒的 gag 序列位于蛋白质的 N
末端。这些附加序列可能改变蛋白质的功能或细胞内的定位，这些改变可能导致
转化。
（2）顺式作用
慢性转化逆转录病毒不含有致癌基因，它们通过插入激活细胞中癌基因表达
（3）反式作用
病毒编码一种转录激活物蛋白如 tax 基因编码蛋白，通过反式作用来刺激细胞内
癌基因的转录
DNA 肿瘤病毒通过与
（4）P53 和
（5）Rb 相互作用，改变细胞周期，从而使细胞转化
2．病毒入侵宿主细胞，在遭受免疫系统的攻击后，有哪些策略逃避免疫应答？
（10 分）
(1) MHC 1 型抗原递呈的抑制，逃脱 CTL 反应
(2) MHC II 型抗原递呈的抑制，
(3) NK 细胞溶细胞作用的抑制
(4) 细胞因子作用的抑制（病毒编码受体，病毒因子）
(5) 阻断干扰素引发的信号转导
(6) 对体液免疫的逃逸，病毒蛋白的变异
(7) 对补体联级反映的逃逸
3．请画图描述病毒的一步生长曲线，并解释曲线的不同阶段所代表的意义（10
分）
隐蔽期
潜伏期
释放期
4．根据病毒基因组以及复制方式的不同，病毒可分为几大类？ （10 分）
全部答对得 10 分，答对 1 个得 1 分，答对 6 个得 6 分，一次类推
（1）dsDNA
（2）ssDNA
（3）dsRNA
（4）ssRNA(-)
（5）ssRNA(+)
（6）ssRNA, 有 DNA 复制中间体
（7）dsDNA, 有 RNA 复制中间体