09-10分子生物學期末試卷答案.doc

福建農(nóng)林大學期末考試試卷參考答案2009 2010學年第 學期課程名稱： 分子生物學 考試時間 120 分鐘 專業(yè) 年級 班 學號 姓名 題號一二三四總得分得分評卷人簽字復核人簽字得分一、填空題（每空0.5分，共10分）1、There are five types of DNA repair, include photo-reactivation repair, _， _，_ and error-prone repair.（切除修復；重組修復；錯配修復）2、The holoenzyme of E.coli RNA polymerase is_，the core enzyme is made up of _，while the_ factor has the ability to recognize specific binding sites.（2；2；）3、The eukaryotes have a well-defined cell cycle.The phase are：G1，_，_ and M.（S；G2）4、Only one strand of a DNA duplex will be transcribed. So the RNA is identical in sequence with another strand of the DNA which is called _，and the template strand is _.（有義鏈；反義鏈）5、In eukaryotes, mRNA processing includes the following steps: addition of at 5end, addition of at 3end, removal of , joining together the ,And these take place in .（M7G帽子結構；poly(A)尾巴；內含子；外顯子；細胞核）6、The structure is a common secondary structural reprensentation of tRNA molecules. The tertiary structure of tRNA molecules is . （三葉草；L）7、In the large 60S subunit of the eukaryote ribosome, there are rRNA, and rRNA, and rRNA. (5S；5.8S；28S) 得分二、名詞解釋（每小題2分，共30分）1、Promoter：RNA聚合酶結合并起始轉錄的一段DNA序列。2、Semi-conservative replication：半保留復制，親代雙鏈DNA以每條鏈為模板，按堿基配對原則各合成一條互補鏈，這樣一條親代DNA雙螺旋，形成兩條完全相同的子代DNA螺旋，子代DNA分子中都有一條合成的“新”鏈和一條來自親代的舊鏈。3、Intron：真核生物DNA編碼序列中間隔的非編碼序列，它們也能被轉錄成RNA，但在mRNA成熟加工中會被切除。4、Transversion：在基因突變中，嘌呤被嘧啶所代替的現(xiàn)象，反之亦然。5、Gene recombination：指由于不同DNA鏈的斷裂和連接而產(chǎn)生的DNA片段的交換和重新組合，形成新的DNA分子的過程。因此，新的DNA分子中含有原來的兩個DNA 分子的片段。6、Hybridization：不同來源的核酸單鏈通過堿基互補配對原則結合成雙鏈的過程。7、Transcription：以DNA為模板，在RNA聚合酶的催化下，合成RNA的過程。8、Proofreading activity：即DNA聚合酶的35外切酶活性，當復制過程中插入錯配堿基時該活性被激活，進而將錯配堿基切除。9、RNA processing：RNA加工，前提RNA轉變?yōu)槌墒霷NA的過程，發(fā)生在細胞核內。10、Triplet code：三聯(lián)體密碼，3個連續(xù)的核苷酸編碼一個氨基酸。11、Chaperone：分子伴侶，幫助蛋白質分子形成正確空間構象的輔助分子。12、Trans-acting element：反式作用元件，指能直接或間接地識別或結合在各類順式作用元件核心序列上參與調控靶基因轉錄效率的蛋白質。13、Open reading frame：特定的核酸序列由一個起始密碼子（AUG/ATG）和三個終止密碼子組成，核酸序列能翻譯為蛋白質序列。14、Ribozyme：核酶，具有催化作用的RNA分子。15、Zinc finger：鋅指，一種常出現(xiàn)在DNA結合蛋白中的一種結構基元。是由一個含有大約30個氨基酸的環(huán)和一個與環(huán)上的4個Cys或2個Cys和2個His配位的Zn2+構成，形成的結構像手指狀。得分三、單項選擇題（每小題1分，共15分）（ D ）1、What is the percentage of A in a piece of RNA if the percentage of C is 30%?A. 30% B. 20%C. 60% D. Unable to calculate with the information provided.（ D ）2、Which of the following is NOT a function of RNA?A. It acts a template during translation.B. It is required for RNA splicing.C. It is essential for the structure of ribosomes.D. It attaches the correct amino acid to tRNA.（ C ）3、Histones are found in close association with DNA. Which of the following statements is incorrect?A. Histone H1 is less evolutionarily conserved than core histones.B. A nucleosome is composed of 146 bp of DNA and a histone octomerC. There are only four types of histonesD. Nucleosomes are evenly distribution within chromatin（ B ）4、The elongation of the lagging strand during DNA synthesis:A. In the 3-5 directionB. Produces Okazaki fragments C. Polymerizes into the direction of fork movementD. Does not require a template strand（ C ）5、Telomeres are found at the end of chromosomes and they are synthesized by telomerase. Which one of the following statements is correct?A. The function of telomerase is to directly elongate the leading strand during DNA replication.B. Telomers code for ribosomal RNA.C. Telomerase is an unusual enzyme made up of RNA template and protein.D. Telomerase is active in all cell types.（ C ）6、Which of the following is correct concerning transcription and DNA replication?A. Only transcription requires a primer.B. Transcription starts at the origin of replication.C. In DNA replication, both the coding and template strands are copied.D. The entire genome is copied in transcription.（ D ）7、Which of the following statements describes a similarity between the structure of DNA and RNA? In both DNA and RNA, A. the nitrogenous base uracil is found.B. there is a hexose sugar.C. the carbon 2 has an hydroxyl group.D. the nitrogenous base is attached to carbon 1.（ D ）8、Regulation of the trytophan operon involvesA. repression (at an operator) B. attenuationC. the concentration of free trytophan D. all of the above（ B ）9、Which of the following is not stop codon? A. TAA B. TAT C. TAG D. TGA（ A ）10、The Shine-Dalgarno sequence in mRNAsA. base pairs to the 3-end of E. coli 16S rRNAB. base pairs to the 5-end of E. coli 16S rRNAC. has a consensus sequence of YNCURACD. is located just downstream of the initiation codon （ C ）11、Which of the following is not bound to the aminoacyl-tRNA synthetase? A. amino acid B. tRNA C. GTP D. ATP （ D ）12、The ribosome scanning model for translation was proposed byA. P. Sharp B. R. RobertsC. T. Cech D. M. Kozak（ D ）13、Most nuclear mRNA introns begin with _ and end with _. A. U, G B. GU, NG C. AG, GU D. GU, AG （ A ）14、Which of the following is the covalent linkage of ubiquitin molecule with the protein damaged? A. Gly B.Lys C. Leu D.Thr（ C ）15、In nuclear mRNA splicing, the intron is released as a A. circular RNA B. linear RNA C. lariat RNA D. a “Y” RNA得分四、問答題（45分）1、Please illuminate the main content of central dogma and draw the sketch map.（8 points）DNA是生物遺傳的主要物質基礎。遺傳信息以特定的脫氧核苷酸序列儲存在DNA分子中（1分）。DNA能準確地自我復制（1分），并把遺傳信息轉錄到mRNA分子上（1分），然后通過mRNA翻譯成為具有特定氨基酸順序的蛋白質（1分），由蛋白質行使各種生物學功能。Crick把這種遺傳信息的流動稱為分子遺傳的中心法則。后來人們又發(fā)現(xiàn)反轉錄病毒可以其RNA作為模板指導合成DNA（1分）；某些病毒RNA可以進行自我復制，即以自身RNA為模板，合成子代RNA（1分）。這些發(fā)現(xiàn)是對中心法則的補充和發(fā)展。 DNA RNA 蛋白質 （2分）2、What is the operon? How the lac operon controls gene expression?（8 points）操縱子是原核生物基因表達調控的單位（1分），包括啟動子、操縱基因和一系列功能上相關的結構基因（1分）。沒有乳糖lacI編碼的阻遏蛋白具有活性牢固結合到操縱基因O上結合在啟動區(qū)的RNA pol不能通過Z、Y、A不能轉錄（和表達）（3分）加入乳糖乳糖（誘導物）與阻遏蛋白結合阻遏蛋白構象變化阻遏蛋白從操縱基因上脫落RNA pol開始Z、Y、A基因的轉錄，表達乳糖被利用（3分） 3、Please write out the enzymes and proteins required in prokaryotic DNA replication，and explain their functions.（7 points）拓撲異構酶：消除DNA超螺旋產(chǎn)生的阻力；（1分）解鏈酶：解開DNA雙鏈，產(chǎn)生單鏈DNA；（1分）SSB：保護解開的DNA單鏈，避免復性；（1分）引物酶：合成RNA引物，為DNA聚合酶提供3末端；（1分）DNA聚合酶III：延長DNA片段，是真正起復制作用的酶；（1分）DNA聚合酶I：負責切除引物并填補引物所在的缺口；（1分）DNA連接酶：連接岡崎片段。（1分）4、What are the characters of expression vectors?（5 points）（1）能夠進行獨立于基因組的自我復制 （1分）（2）容易從細胞中分離提取 （1分）（3）含有多克隆位點，允許外源片段的插入 （1分）（4）含有至少一個選擇標記 （1分）（5）具有啟動子、終止子等表達元件 （1分）5、Please illuminate the function of the cap structure of mature mRNA in 5emd.（5 points） (1) 對5外切核酸酶形成屏障，保護和穩(wěn)定轉錄產(chǎn)物（2分） (2) 有助于前體mRNA的剪接和轉運到細胞質（2分） (3) 提高翻譯的效率（1分）6、Please illuminate the difference between the initial tRNA molecule and the tRNAMet in elongation in E.coli. （5 points）（1）只有起始tRNA分子的蛋氨酸甲?；羌柞；膄met-tRNA也能起始，但效率不高，因為甲酰化是與tRNA分子結合