生物专业英语词汇d

1、.dDeath rate the ratio between deaths and individuals in a specified population at a particular time.Deoxyribonucleic acid (DNA) a nucleic acid composed of two polynucleotide strands wound around a central axis to form a double helix; the repository of genetic information. Nucleic acid that function

2、s as the physical carrier of inheritance for 99% of all species. The molecule is double-stranded and composed of two strands in an antiparallel and complementary arrangement. The basic unit, the nucleotide, consists of a molecule of Deoxyribose sugar, a phosphate group, and one of four nitrogenous b

3、ases.Deoxyribose five-carbon sugar found in Nucleotides of DNA. Diabetes a disorder associated with defects in Insulin action. 糖尿病因其痛苦的症状之一而得名。此糖尿病因其痛苦的症状之一而得名。此病症闻名于希腊语病症闻名于希腊语diabetes，是动词，是动词diabainein派生出的单词，由前缀派生出的单词，由前缀dia-“穿过，隔开穿过，隔开”和单和单词词 bainein“走，站走，站”构成。动词构成。动词diabeinein 表表示示“跨过，走过或两条腿分开站着

4、跨过，走过或两条腿分开站着”；因此，其；因此，其派生词派生词diabetes表示表示“一个人叉腿站着一个人叉腿站着”，或专，或专指指“指南针，虹吸管指南针，虹吸管”。在。在diabetes 使用使用“虹虹吸管吸管”是表示排尿量过多的一种病的名称。是表示排尿量过多的一种病的名称。.Dicots one of the two main types of flowering plants; characterized by having two Cotyledons, Floral organs arranged in cycles of four or five, and leaves with

5、reticulate veins; include trees (except Conifers) and most ornamental and crop plants. =dicotyledon 双子叶植物monocotyledon 单子叶植物. Digestion the process of breaking down food into its molecular and chemical components so that these nutrient molecules can cross plasma membranes. . Digestive system one of

6、eleven major body organ systems in animals; converts food from the external environment into nutrient molecules that can be used and stored by the body and eliminates solid wastes; involves five functions: movement, secretion, Digestion, absorption, and elimination. Dinosaurs any of the mesozoic(中生代

7、的) reptiles. 恐龙Greek deinos monstrous Greek sauros lizard .Diploid cells that contain homologous chromosomes. The number of Chromosomes in the cells is the diploid number and is equal to 2n (n is the number of homologous pairs).Divergent evolution the divergence of a single interbreeding population

8、or species into two or more descendant species.Diversity the different types of organisms that occur in a Community.biodiversity.DNA hybridization the formation of hybrid DNA molecules that contain a strand of DNA from two different species. 杂交.DNA ligase in recombinant DNA technology, an enzyme tha

9、t seals together two DNA fragments from different sources to form a recombinant DNA molecule.连连接酶接酶. DNA polymerase in DNA replication, the enzyme that links the Complementary Nucleotides together to form the newly synthesized strand.Dominance the property of one of a pair of alleles that suppresses

10、 the expression of the other member of the pair in heterozygotes.Double fertilization a characteristic of angiosperms in which a pollen tube carries two sperm cells to the female Gamehyte in the ovule. One sperm cell fuses with the egg cell and gives rise to a Diploid embryo， the other sperm cell fu

11、ses with the two polar cells to form a triploid cell that develops into the Endosperm.Eccrine glands sweat glands that are linked to the sympathetic nervous system and are widely distributed over the body surface. 外分泌腺 ec=ex; crine=krinein to secrete.Ecology the study of how organisms interact with

12、each other and their physical environment. Eco=house.Ecosystem the Community living in an area and its physical environment.Ecotype a subdivision of a species; a stage in the formation of a species such that reproductive isolation has occurred.Ectoderm the outer layer of cells in embryonic developme

13、nt; gives rise to the skin, Brain, and Nervous system. 外胚层 derm=skin.Ectotherms animals with a variable body temperature that is determined by the environment. Examples: fish, frogs, and reptiles. 冷血动物；变温动物 cold-blooded animal therm=heat.Electron acceptor a molecule that forms part of the Electron t

14、ransport system that transfers electrons ejected by Chlorophyll during photosynthesis. Part of the energy carried by the electrons is transferred to ATP, part is transferred to NADPH, and part is lost in the transfer system.Electron transport 1) a series of coupled oxidation/reduction reactions wher

15、e electrons are passed like hot potatoes from one membrane-bound protein/enzyme to another before being finally attached to a terminal Electron acceptor (usually oxygen or NADPH). ATP is formed by this process. 2) coupled series of oxidation/reduction reactions during which ATP is generated by energ

16、y transfer as electrons move from high reducing state to lower reducing state. . Embryo term applied to the zygote after the beginning of Mitosis that produces a multicellular structure. 胚.Embryo sac alternate term applied to the angiosperm female Gamehyte contained within a megaspore.胚囊.Endocrine s

17、ystem one of eleven major body organ systems in animals; a system of glands that works with the Nervous system. Endoderm the inner layer of cells in embryonic development that gives rise to organs and tissues associated with Digestion and respiration. 内胚层.Endoplasmic reticulum (ER) a network of memb

18、ranous tubules in the Cytoplasm of a cell; involved in the production of phospholipids, proteins, and other functions. Rough ER is studded with ribosomes; smooth ER is not. Endosperm a food storage tissue that provides nutrients to the developing Embryo in angiosperms; formed from the triploid cell

19、produced when a sperm cell fertilizes the central cell. Some Endosperm is solid (as in corn), some is liquid (as in coconut). 胚乳 spermsemen 精液.Endosymbiosis theory that attempts to explain the origin of the DNA-containing Mitochondria and Chloroplasts in early Eukaryotes by the engulfing of various

20、types of bacteria that were not digested but became permanent additions to the ancestral “eukaryote”. 内共生.Endotherms animals that have the ability to maintain a constant body temperature over a wide range of environmental conditions. 温血动物，恒温动物.Energy flow the movement of energy through a Community v

21、ia feeding relationships. . Energy of activation the minimum amount of Energy required for a given reaction to occur; varies from reaction to reaction. 活化能.Enzymes protein molecules that act as catalysts in biochemical reactions. . Epidermis The outermost layer of skin consisting of several layers.

22、epi- 表“在之上”。 表皮.Ethylene a gaseous plant hormone that stimulates fruit ripening and the dropping of leaves. 乙烯. Eukaryote a type of cell found in many organisms including single-celled protists and multicellular fungi, plants, and animals; characterized by a membrane-bounded Nucleus and other membra

23、neous organelles; an organism composed of such cells. The first eukaryotes are encountered in rocks approximately 1.2-1.5 billion years old. . Evaporationthe part of the hydrologic cycle in which liquid water is converted to vapor and enters the atmosphere. 蒸发(作用).Evolution 1) the change in life ove

24、r time by Adaptation, variation, over-reproduction, and differential survival/reproduction, a process referred to by Charles Darwin and Alfred Wallace as Natural selection. 2) descent with modification. volu=volv=roll. Evolutionary tree a diagram showing the evolutionary history of organisms based on differences in amino acid sequences. Organisms with fewer differences are placed closer together while