生物專業(yè)英語分析解析

1、Cell Cycle The cell cycle, or cell-division cycle, is the series of events that take place in a cell leading to its division and duplication (replication). In cells without a nucleus (prokaryotic), the cell cycle occurs via a process termed binary fission. In cells with a nucleus (eukaryotes), the c

2、ell cycle can be divided in two periods: Interphaseduring which the cell grows, accumulating nutrients needed for mitosis and duplicating its DNA. The mitosis (M) phase, during which the cell splits itself into two distinct cells, often called daughter cells and the final phase, cytokinesis, where t

3、he new cell is completely divided. The cell-division cycle is a vital process by which a single-celled fertilized egg develops into a mature organism, as well as the process by which hair, skin, blood cells, and some internal organs are renewed. Before a cell can enter cell division, it needs to tak

4、e in nutrients. All of the preparations are done during the interphase. Interphase proceeds in three stages, G1, S, and G2. Cell division operates in a cycle. Therefore, interphase is preceded by the previous cycle of mitosis and cytokinesis. Interphase is also known as preparatory phase, in this st

5、age nucleus and cytosol division does not occur. The cell prepares to divide. Interphase G1 Phase The first phase within interphase, from the end of the previous M phase until the beginning of DNA synthesis is called G1 (G indicating gap). It is also called the growth phase. During this phase the bi

6、osynthetic activities of the cell, which had been considerably slowed down during M phase, resume at a high rate. This phase is marked by the use of 20 amino acids to form millions of proteins and later on enzymes that are required in S phase, mainly those needed for DNA replication. Duration of G1

7、is highly variable, even among different cells of the same species. It is under the control of the p53 gene. S Phase The ensuing S phase starts when DNA synthesis commences; when it is complete, all of the chromosomes have been replicated, i.e., each chromosome has two (sister) chromatids. Thus, dur

8、ing this phase, the amount of DNA in the cell has effectively doubled, though the ploidy of the cell remains the same. During this phase, synthesis is completed as quickly as possible due to the exposed base pairs being sensitive to external factors such as any drugs taken or any mutagens (such as n

9、icotine). G2 Phase The cell then enters the G2 phase, which lasts until the cell enters mitosis. Again, significant biosynthesis occurs during this phase, mainly involving the production of microtubules, which are required during the process of mitosis. Inhibition of protein synthesis during G2 phas

10、e prevents the cell from undergoing mitosis. Mitosis Mitosis is the process by which a eukaryotic cell separates the chromosomes in its cell nucleus into two identical sets in two nuclei. It is generally followed immediately by cytokinesis, which divides the nuclei, cytoplasm, organelles and cell me

11、mbrane into two cells containing roughly equal shares of these cellular components. Mitosis and cytokinesis together define the mitotic (M) phase of the cell cycle - the division of the mother cell into two daughter cells, genetically identical to each other and to their parent cell. This accounts f

12、or a p p r o x i m a t e l y 1 0 % o f t h e c e l l cycle. Mitosis occurs exclusively in eukaryotic cells, but occurs in different ways in different species. For example, animals undergo an open mitosis, where the nuclear envelope breaks down before the chromosomes separate, while fungi such as Asp

13、ergillus nidulans and Saccharomyces cerevisiae (yeast) undergo a closed mitosis, where chromosomes divide within an intact cell nucleus. Prokaryotic cells, which lack a nucleus, divide by a process called binary fission. Meiosis Meiosis is a special type of cell division necessary for sexual reprodu

14、ction in eukaryotes. The cells produced by meiosis are gametes or spores. In many organisms, including all animals and land plants (but not some other groups such as fungi), gametes are called sperm and egg cells. Whilst the process of meiosis bears a number of similarities with the life-cycle cell

15、division process of mitosis, it differs in two important respects: The outcome of meiosis is four (genetically unique) haploid cells, compared with the two (genetically identical) diploid cells produced from mitosis The chromosomes in meiosis undergo a recombination which shuffles the genes producin

16、g a different genetic combination in each gamete, compared with the co- existence of each of the two separate pairs of each chromosome (one received from each parent) in each cell which results from mitosis Glossary Anaphase 后期后期; 分裂后期分裂后期 Cell plate 窩眼盤窩眼盤; 細胞板細胞板 Centromere sentr,mi n. 生生 著絲點著絲點,

17、著絲粒著絲粒 Chalone klun n. 生化生化 抑素抑素 Chromatid krumtid n. 染色分體染色分體 Chromatin krumtin n. 核染質(zhì)核染質(zhì), 染色質(zhì)染色質(zhì) Astral adj. 星形 的； 星 際的 Phycoplast n. 藻質(zhì)體藻質(zhì)體; phragmoplast n. 成膜體成膜體; coalesce vi. 聯(lián)合，合并聯(lián)合，合并 ; perforate vt. 穿孔于，在穿孔于，在上打眼上打眼; plasmodesmata (復復)胞間連絲胞間連絲 Lamella n. 薄層；薄層； 薄片；薄片； 瓣；瓣； 鰓鰓 Terminology n.

18、 專專 門名詞；門名詞； 術(shù)語，術(shù)術(shù)語，術(shù) 語學；語學； 用辭用辭 Cytokinesis ,saitukaini:sis n. 細胞漿移動細胞漿移動, 原漿移動原漿移動; 胞質(zhì)分裂胞質(zhì)分裂 Diploid diplid a. 雙重的雙重的, 雙倍性的雙倍性的, 倍數(shù)倍數(shù) 的的 n. 倍數(shù)染色體倍數(shù)染色體 Haploid hplid n. 生物生物 單倍體單倍體, 僅有一僅有一 組染色體的細組染色體的細 a. 單一的單一的 Histone histun n. 生化生化 組蛋白組蛋白 homologous pair 同源染色體對同源染色體對 Cytokinesis Cytokinesis, fr

19、om the greek cyto- (cell) and kinesis (motion, movement), is the process in which the cytoplasm of a single eukaryotic cell is divided to form two daughter cells. It usually initiates during the late stages of mitosis, and sometimes meiosis, splitting a mitotic cell in two, to ensure that chromosome

20、 number is maintained from one generation to the next. Interphase int(:)feiz n. 中間相中間相 (界面界面,相相 間的間的)；a. 相間的相間的 Karyotype kritaip n. 生物生物 染色體組染色體組 型；核型型；核型 Meiosis maiusis n. 減少；減數(shù)分裂減少；減數(shù)分裂 Metaphase metfeiz a. 中期中期, 轉(zhuǎn)位期轉(zhuǎn)位期 metaphase plate 赤道板；中期板赤道板；中期板 Karyotype A karyotype (Greek karyon = kernel,

21、 seed or nucleus) is the number and appearance of chromosomes in the nucleus of a eukaryotic cell. The term is also used for the complete set of chromosomes in a species, or an individual organism. Karyotypes describe the number of chromosomes, and what they look like under a light microscope. Atten

22、tion is paid to their length, the position of the centromeres, banding pattern, any differences between the sex chromosomes, and any other physical characteristics. The preparation and study of karyotypes is part of cytogenetics. Mitosis mitusis n. 有絲分裂有絲分裂, 間接核分裂間接核分裂 Nucleosome nju:klisum n. 生化生化

23、核小核小 體體 Prophase prufeiz n. （分裂）前期（分裂）前期 Spindle spindl n. 紗錠紗錠, 紡錘紡錘, 軸；軸；v. 變變 細長細長 Telophase telfeiz n.（分裂）（分裂） 末期末期 Repository ripzitri n. 貯藏室貯藏室 (博物館博物館, 資源豐富地區(qū)資源豐富地區(qū)) Coil kil n. 卷卷, 騷動；騷動；v. 盤繞盤繞, 卷；卷； n. 【電電】線圈線圈, 繞組繞組 Cluster klst n. 串串, 叢叢, 群；群；v. 聚合聚合, 成成 串串, 叢生叢生, 使使.聚集聚集 Pictorial pikt:

24、ril a. 繪畫的繪畫的; n. 畫報畫報 Immortal im:tl a. 不朽的不朽的; n. 不朽的人物不朽的人物 Metabolism metblizm n. 新陳代謝新陳代謝 Condense kndens v. 濃縮濃縮, 摘要摘要, 縮短縮短 Replicate replikit v. 折疊折疊, 復制復制, 模寫模寫; n. 八音階間隔的反復高低音八音階間隔的反復高低音 Kinetochore kini:tk: n. 生生動粒動粒, 著絲著絲 粒粒, 著絲點著絲點 Centriole sentriul n. 生生細胞中心粒細胞中心粒, 中中 心體心體 Pinch pint

25、n. 捏捏, 撮撮, 困苦困苦; v. 掐掐, 使使.困困 苦苦, 節(jié)儉節(jié)儉 Progeny prdini n. 子孫子孫(結(jié)果結(jié)果, 次級粒子次級粒子) Synapsis sinpsis 生生染色體結(jié)合染色體結(jié)合, 聯(lián)會聯(lián)會 Align lain v. 排列排列, 調(diào)整調(diào)整, 定中心定中心, 校直校直, 使結(jié)盟使結(jié)盟, 使成一行使成一行 Catastrophic ,ktstrfik a. 悲慘的悲慘的, 災難災難 的的 Deleterious ,delitiris a. 有害于有害于, 有毒的有毒的 Gamete gmi:t n. 配偶子配偶子 Tetrad tetrd 四位組四位組 Syn

26、apsis Synapsis (also called syndesis) is the pairing of two homologous chromosomes that occurs during meiosis. It allows matching-up of homologous pairs prior to their segregation, and possible chromosomal crossover between them. Synapsis takes place during prophase I. When homologous chromosomes sy

27、napse, their ends are first attached to the nuclear envelope. These end-membrane complexes then migrate, assisted by the extranuclear cytoskeleton, until matching ends have been paired. Then the intervening regions of the chromosome are brought together, and may be connected by a protein-RNA complex

28、 called the synaptonemal complex. While autosomes undergo synapsis during meiosis, sex chromosomes often remain unpaired. Text Within the nucleus are the chromosomes- tightly coiled strands of DNA and clusters of associated proteins. Each long strand of DNA combines with histones and nonhistone to m

29、ake up the substance chromatin. SUMO proteins are similar to ubiquitin, and SUMOylation is directed by an enzymatic cascade analogous to that involved in ubiquitination Karyotypes reveals that in most cells all but sex chromosomes are present as two copies, referred to as homologous pairs. Organisms

30、 whose cells contain two sets of parental chromosomes are called diploid; those with cells containing a single set of parental chromosomes are called haploid. Many cells in multicellular organisms, including animal muscle and nerve cells, either slow the cycle or break out of it altogether. The four

31、th phase of the cell cycle is M phase, the period of mitosis, during which the replicated chromosomes condensed and move and the cell divides. At the beginning of prophase the chromosomes each consist of two highly condensed chromatids attached to each other at a centromere Eventually the chromosomes become arranged in a plane (called the metaphase plate) at a right angle to the spindle fibers. During telophase nuclear envelopes begin to form around each set of chromosomes, and division of the