微生物答案v1.3個(gè)人版

1、微生物復(fù)習(xí)題答案（1.3 版 ）個(gè)人版 版本說明: 根據(jù)打印版（1.3） ，準(zhǔn)備的時(shí)候?qū)φ諘行┑胤接懈膭?dòng)，但是沒有刻意標(biāo)出來。一部分問題加上了中文答案，大多數(shù) 是從中文的那本書上抄的。也有為了方便記憶自己翻譯的，準(zhǔn)確度可能就不能保證了。藍(lán)色的部分是我認(rèn)為比較好的 答案（因?yàn)橛行╊}的答案不只一個(gè)版本） ，或者自己認(rèn)為比較重要的部分（完全是個(gè)人意見，僅供參考） 。 另外一個(gè)背誦版本是我復(fù)習(xí)的時(shí)候自己練習(xí)背誦用的，所以答案比較精簡(jiǎn)一些，是把個(gè)人認(rèn)為的最佳最簡(jiǎn)單的答案寫 上去了?？赡芡暾圆粔颍粨粲糜眠€是可以的。 希望大家繼續(xù)補(bǔ)充！ 2004. 1 許 1-22 題 說明： 參考了陳業(yè)、九字班打印

2、版，但有些還是認(rèn)為不對(duì)，所以考證了書。應(yīng)該說有些題比陳業(yè)版詳細(xì)，比 9 字班簡(jiǎn)潔，源 于書而又不完全相同。有些題目如果時(shí)間緊的話就背一下關(guān)鍵詞，具體解釋就算了。 每道題都斟酌過了，有些不確認(rèn)的均有說明。 Complete Question List for Microbiology 1. Introduction to Microbiology 1What is Microbiology? The study of microorganisms, a large and diverse group of organisms that exist as single cells or cell

3、clusters, include viruses. 2hat are Microorganisms? A large and diverse group of microscopic organisms that exist as single cells or cell clusters(including prokaryotes and eukaryotes), also include viruses which are not cellular. 3What are Prokaryotes? Cells lacking a nucleus and other organelles.

4、Including Bacteria archaea actinomycetes（放線菌）（放線菌） mycoplasma（支原體）（支原體） rickettsia（立克次氏體）（立克次氏體） chlamydia（衣原體）（衣原體） cyanobacteria（藍(lán)細(xì)菌）（藍(lán)細(xì)菌） 4What are Eukaryotic Microorganisms? Cells possessing a membrane-enclosed nucleus and usually other organelles. Including Algae fungi slime（粘液）（粘液）-mold protoz

5、oa 5Structural differences between P P Ring; S-M Ring Mot protein, Fli protein Structure: made of several proteins, most of which are anchored in the cell wall and membrane. Function: movement(mobility) 29.What is the energy source for the flagellum?(P82) Proton motive force, proton across membrance

6、 through Mot complex drives rotation of the flagellum,and 1000proton per single rotation of the flagellum 以上是對(duì)的 30.What types of cytoplasmic inclusions are formed by prokaryotes?(P87) PHA, glycogen, polyphosphate, elemental sulfur, magnetosomes (PHB granules, glycogen granules, polyphosphate granule

7、s, sulfur granules, magnetosomes) 我有一個(gè)問題：gas vesicles, endospores 算不算 cytoplasmic inclusion 呢？ “Polyhydroxyalkanoates (carbon source and energy storage materials)多羥基鏈烷酸鹽 Glycogen (carbon source and energy storage materials) Polyphosphate 聚磷酸鹽 Elemental sulfur Magnetosomes (magnetotaxis of Aquaspiril

8、lum magnetotacticum)“ 以上 ppt Nutrition and Metabolism 31.Macronutrients and micronutrient, defined medium and complex medium(P104105) Nutrients are starting materials for hundreds of chemical compounds present inside a living cell. Elements required in fairly large amounts are so-called macronutrien

9、t(including C, H, O, N, S, P, K, Mg, Ca, Na, Fe); while metals（？） needed in very small amounts are called micronutrients. Micronutrients play a structural role in various enzymes(Cr, Co, Cu, Mn, Mo, Ni, Se, W, V, Zn, Iron Fe). Chemically Defined media are prepared by adding precise amounts of highly

10、 purified inorganic or organic chemicals into distilled water. Examples are glucose, sucrose, acetate, pyruvate, malate, fatty acids, alkanes et al. Complex media employ digests of casein, beef, soybeans, yeast cells, or any of a number of other highly nutritious substances. 32.Growth factors(P106)

11、Growth factors are organic compounds required in very small amounts.and only by some cells ,including vitaminA.,purine,pyrimidines（？）. 33.Environmental factors affect growth of microorganisms(Chapter 5) Temperature, pH values, osmotic effects and oxygen 34.How to prepare a medium for cultivation mic

12、roorganisms(P108) Two aspects must be highlighted: one is the understanding of the nutritional requirements the given microorganisms need, and the other is supplying essential nutrients in the proper form and proportions in a culture medium. 35.Pure culture access and cell growth calculation （是指細(xì)胞計(jì)數(shù)

13、還是細(xì)胞生長(zhǎng)計(jì)算？）(P141143) Proper nutrient and conditions ,keep other organisms out. By streak plate technique（劃線分離單菌落） Cell growth in exponential phase can be expressed as follows: or n NN2 0 2lg lg 0 N N n slope = lg2 / g Population growth is measured by following changes in the number of cells or weight

14、 of cell mass: Total Cell Counting (direct microscopic count)- counting a sample under the microscope, samples either dried on slides or in liquid. Viable Counting (plate counting or colony counting-including two methods: spread plate method and pour plate method. 補(bǔ)充：turbidimetric measurement (濁度) 3

15、6.How cells divide themselves and how to do viable count (P137 and P142) The way cell divides themselves: binary fission (most common), budding and, multiple fission (uncommon). How to do viable count: performance of a viable count is to determine the number of cells in the sample capable of forming

16、 colonies on a suitable agar medium. There are two ways to perform the task: one is so-called spread plate method, and the other pour plate method. In spread plate method, three steps are employed: dilution, plating and incubation. 37.Microbial cell growth cycle (P139) Growth cycle of microbial popu

17、lations can be divided into several distinct phases: lag phase, exponential phase (or log phase), stationary phase and death phase. 38.Exponential growth maintenance (P145) This can be achieved by chemostat. By controlling the dilution and concentration of nutrients. 39.How to name microorganisms th

18、at grow best at a temperature? (P148 圖) 0 部分滅菌 pasteurization) Radiation(microwave, UV, X-ray, r-ray, electrons) Filtration (depth filter, membrane filter, nucleation track filter) Chemical(germicides): -cidal agent(kill or inhibit,不可逆); -static agent(inhibit growth but not kill bacteria，可逆) disinte

19、ctants(kill microorganisms and are used on inanimate object) antisepeics(kill or inhibit and are sufficiently nontoxic to be applied to living tissue) 體內(nèi)抗菌 chemotherapeutic agent: (have selective toxicity) 1 synthetic agent: growth factor agent, quinolines 2 antibiotics 43.On what sites do antibioti

20、cs act on cells? Cell wall synthesis, folic acid（葉酸？） metabolism, cytoplasmic membrane structure, DNA gyrase（促旋酶）, DNA directed RNA polymerase, inhibition of protein synthesis through tRNA or ribosome (30s.50s) 44. How to preserve food? Sterilization（消毒，滅菌）, lower temperature, pH acidity, low water

21、availability, canning, chemical food preservation Question4566 45.Describe the DNA replication process. DNA synthesis begins at a unique location called the origin of replication. The double helix is unwounded by helicase and is stabilized by single stranded binding protein. DNA polymerase (generall

22、y III) is then bound to each of the DNA strands. The extension of the DNA replication is occurs continuously on the leading strand, but discontinuously on the lagging strand. In the leading strand(53), replication is from 5end to 3end according to “complementary principle”. In the lagging strand(35)

23、, replication is also from 5end to 3end pieces by pieces, and primer is needed. The primer is synthesized by primase，and removed by DNA polymerase I. Finally, the pieces of DNA is linked by ligase. Most errors in base pairing are corrected by proofreading functions associated with the action of DNA

24、polymerase. 46.What proteins are involved in initiation of DNA synthesis (DNA replication fork)? helicases , single-stranded binding proteins. 47.How do leading and lagging strands replicate? leading strand; DNA synthesis occurs continuously from the 5end to 3end. Lagging strand: DNA synthesis occur

25、s discontinuously. 參見第 45 題。 48. What are enzymes involved in replicating the lagging strand? DNA primase, DNA polymerase III and I , DNA ligase. 49. What are the differences between replicating circular DNA and linear DNA? For linear DNA replication , there is one problem: at the extreme 5-end of e

26、ach strand of linear DNA, even if the RNA primer is very short and there is a special enzyme to remove it, no DNA polymerase can replace it with DNA since all DNA polymerase require a primer. So there are many ways to solve this problem, such as sticky ends, direct repeats, Using a protein primer or

27、 telomerase and so on. 2).Questions on RNA 50. What structural roles has RNA played? Messenger RNA (mRNA) Ribosomal RNA (rRNA) Transfer RNA (tRNA) Catalytic RNA: Ribozyme 51. Describe the transcription process? The initiation and termination sites are specific nucleotide sequences on the DNA. RNA po

28、lymerase moves down the DNA chain, causing temporary opening of the double helix and transcription of one of the DNA strands. When a termination site is reached, chain growth stops and the mRNA and polymerase are released. (完整版)RNA polymerase recognizes special DNA sequence called promoter, binds it

29、, and open up the double helix there. As the polymerase moves, it causes the DNA to unwind in short segments, transcription of one of DNA strands occurs, and the DNA double helix close again. Once a small portion of RNA has been formed, the sigma factor dissociates, and the elongation process is car

30、ried out by the core enzyme alone. When a termination site is reached, chain growth stops and the mRNA and polymerase are released， and the opened DNA closes into the original double helix. 52. How is transcription terminated? (修改版)Termination of transcription occurs at specific base sequence on the

31、 DNA. A common termination sequence on the DNA is one containing an inverted repeat with a central nonrepeating segment. When such a DNA sequence is transcribed, the RNA can form a stem-loop structure by intrastrand base pairing. When such stem-loop structures are followed by runs of runs of uridine

32、s, they are effective transcription terminators. Other termination sites are regions where a GC-rich sequence is followed by a AT-rich sequence. Such kind of structures lead to termination without addition of any extra factors and are sometimes termed intrinsic terminators. Other types of terminator

33、 sequences have been discovered that require protein factors in addition to RNA polymerase in order to function. However, remember that RNA is transcribed from DNA, and so transcription termination is ultimately determined by specific nucleotide sequences on the DNA. 53. What is a promotor and what

34、is its function? （補(bǔ)充版）Promoter is a specific DNA sequences at which RNA polymerase can bind, and which plays a key role in the initiation of RNA synthesis. Its orientation determines which strand of DNA will be transcribed. Its efficiency determines the efficiency of RNA transcription. 54. Polygenic

35、 or polycistronic mRNA In prokaryotes genetic elements, genes coding for related enzymes are often clustered together. In these situations the RNA polymerase proceeds down the chain and transcribes the whole series of genes into a single long mRNA molecule. A mRNA coding for such a group of genes is

36、 called a polygenic or polycistronic mRNA 55. What is an operon? Operon is a complete unit of gene expression, often involving genes coding for several polypeptides on a polycistronic mRNA or genes coding for ribosomal RNA. In some cases, the transcription of the mRNA for an operon is under the cont

37、rol of a specific region of the DNA, the operator, which is adjacent to the coding region of the first gene in the operon. 56. Describe the RNA processing. the conversion of a precursor RNA into a mature RNA is called RNA processing. In prokaryotes and eukaryotes, tRNAs and rRNAs are made initially

38、as long precursor molecules, which are then cut to make the final mature RNAs. In eukaryotes, and much less commonly in prokaryotes, mRNA is also the result of processing a pre- mRNA, which needs to be spliced to remove the introns and join the exons. The mRNAs of eukaryotes need two more processing

39、 steps: capping and tailing. 57. What is a ribozyme? For example? All RNA molecule that can catalyze chemical reactions. Self-splicing ribozymal intron of the protozoan Tetrahymena 3).Translation 58. Describe the translation process, Although a continuous process, protein synthesis can be thought of

40、 as occurring in a number of discrete steps: Initiation: In prokaryotes initiation alwaus begins with a free 30S ribosome subunit, and an initiation complex forms consisting of a 30S ribosome subunit, mRNA, formylmethionine tRNA, and initiation factors. GTP is required for this step. To this initiat

41、ion complex a 50S ribosome subunit is added to make the active 70S ribosome. Prokaryotic ribosomes recognize Shine-Dalgarno sequence, eukaryotic ribosomes typically recognize mRNAs 5-cap. AUG is the only start codon for eukaryotes, but can be replaced by GUG and some other rare codons in prokaryotes

42、. Formylmethinine tRNA bind to the start codon in bacteria, whose formyl group will be removed. In Eukarya and Archaea, initiation begins with methionine instead.(and this amino acid is often removed by a specific protease after translation). Elongation: There are three sites on the ribosome: the ac

43、ceptor site, where the charged tRNA first combines; the peptide site, where the growing polypeptide chain is held; and an exist site. During each step of amino acid addition, the mRNA advances three nucleotides(one codon), and the tRNA moves from the acceptor to the peptide site as a new peptide bon

44、d is formed. Termination-release: when the stop codon is met that does not specify an AA-tRNA, no tRNA binds but instead the release factors read the chain-terminating signal and serve to cleave the attached polypeptide from the terminal tRNA. Following this, the ribosome dissociates, and the subuni

45、ts are the free to form new initiation complex. Polypeptide folding: many proteins require the assistance of other protein called molecular chaperones for proper folding or for assembly into larger complexs. 59.What are the differences between prokaryotic and eukaryotic ribosomes? ProkaryoticEukaryo

46、tic Size 70s(30s+50s)80s(40s+60s) Small subunit Number of proteins RNA size(number of bases) 30s 21 16s(1500) 40s 30 18s(2300) large subunit Number of proteins RNA size(number of bases) 50s 34 23s(2900) 5s(120) 60s 50 28s(4200) 5.8s(160) 5s(120) Other Can use polycitronic mRNA because the ribosome c

47、an find each initiation site within a message Cannot translate polyistronic mRNA(typical recognize an mRNA by its 5cap and initiate only at the 1st initiation coden) 60.What are involved in initiation of protein synthesis? Begin with a free 30s ribosome subunit and an initiation complex forms consis

48、ting of 30 S ribosome subunit, mRNA, formylmethionine tRNA (Start codon AUG), initiation factors and Guanosine triphosphate. 61.What are polysomes and its function? When several ribosomes are simultaneously translating a single message, the complex is called a polysome. Polysomes increase the speed

49、and efficiency of mRNA translation, and because each ribosome acts independently of the others, each ribosome in a polysome complex can make a complete polypeptide 62. What is the function of molecular chaperones? Molecular Chaperones assist many proteins for proper folding or for assembly into larg

50、e complexes.The undolded or improperly folded protein enters the molecular chaperone where it is folded and the released. Energy for the folding comes from ATP. Other cellular chaperones are involved in carrying the unfolded protein to the chaperonin. In addition to fold the newly synthesized protei

51、ns, chaperones also can refold proteins that have partially denatured in the cell. 63.Start codon and stop codon? Several three consecutive nucleotides coding for the initiation of protein synthesis(translation) are called start codons; Several three consecutive nucleotides coding for the terminatio

52、n of protein synthesis(translation) are called stop codons; 64.Universal codons? Universal code is the exact same code used by all living systems. (the answer is not codons) 65.Open Reading Frame (ORF)? A RNA base sequence which contains a start codon (typically AUG) followed by some number of codon

53、s and then a stop codon in the same frame as the start codon. 66.Bioinformatics? The subject combined of computer and molecular biology（好象生物物理的答案里面有） 生物信息學(xué)是一門新興的交叉學(xué)科。它是研究在計(jì)算機(jī)和網(wǎng)絡(luò)大發(fā)展、各種生物數(shù)據(jù)庫(kù)迅猛增長(zhǎng)形勢(shì)下如何組織實(shí)驗(yàn)數(shù)據(jù)、并 從數(shù)據(jù)中提取生物學(xué)知識(shí)、進(jìn)行生物學(xué)基礎(chǔ)研究的一門科學(xué)。 Virus 67. What are viruses? How to classify viruses? Viruses are g

54、enetic elements that can replicate independently of cells chromosomes but not independently of cells themselves. A noncellular genetic element that enlists a cell for its own replication, it has an extracellular state. 病毒是一種獨(dú)立于細(xì)胞染色體而依賴于細(xì)胞進(jìn)行復(fù)制的遺傳因子。 According to hosts: bacterial viruses animal viruse

55、s plant viruses According to nucleic acid structure: DNA viruses RNA viruses; RNA-DNA viruses 68. How are viruses different from bacteria? Viruses have smaller sizes and have either DNA or RNA as genetic material. They do not have cellular structures. They need hosts. 69.Describe vital structure. Th

56、ey have nucleic acid in the capsid. Many have complex membranous structures surrounding the nucleocapsid ,called envelope. Some are more complex, being composed of several separate parts with separate shape and symmetries. 70.What are the two common symmetry structures? Helical and icosahedral (二十面體

57、)symmetry 71.What are the most common enzymes brought with by viruses themselves? How to grow viruses? Reverse transcriptase in retroviruses Neuraminadase: break down glycoprotein,aiding liberation of the virus Lysosome: bacteriophage Methods of growing viruses: Bacteriophage: bacterial Cultures Ani

58、mal viruses: Tissue or cell cultures 72.How to quantify viruses? In general, viruses are qualified by measuring their effect on the host cells that they infect. It is common to say a virus infectious unit, which is the smallest unit that causes a detectable effect when placed with a susceptible host

59、 . By determing the number of infectious units per volume of fluid, a measure of virus quantity can be obtained. 73. What is the virus life circle? (1)Attachment (adsorption) (2)Penetration (injection) animal virus: endocytosis (3) Early steps in replication (4) Replication (5) Synthesis of protein subunits (6) Assembly and packaging (7) Release 74.How host cell protect themselves from virus attacks? (1)Restriction enzyme destroy invasion of foreign DNA. Cells protect themselves from destruction by restriction enzy