生物专业英语词汇整理1.docx

1、生物专业英语词汇整理1Lesson Two（2学时）PhotosynthesisPhotosynthesis occurs only in the chlorophyllchlorophyll叶绿素-containing cells of green plants, algae藻, and certain protists 原生生物and bacteria. Overall, it is a process that converts light energy into chemical energy that is stored in the molecular bonds. From th

2、e point of view of chemistry and energetics, it is the opposite of cellular respiration. Whereas 然而 cellular细胞的 respiration 呼吸is highly exergonic吸收能量的 and releases energy, photosynthesis光合作用 requires energy and is highly endergonic.光合作用只发生在含有叶绿素的绿色植物细胞，海藻，某些原生动物和细菌之中。总体来说，这是一个将光能转化成化学能，并将能量贮存在分子键中，从

3、化学和动能学角度来看，它是细胞呼吸作用的对立面。细胞呼吸作用是高度放能的，光合作用是需要能量并高吸能的过程。Photosynthesis starts with CO2 and H2O as raw materials and proceeds through two sets of partial reactions. In the first set, called the light-dependent reactions, water molecules are split裂开 (oxidized), 02 is released, and ATP and NADPH are form

4、ed. These reactions must take place in the presence of 在面前 light energy. In the second set, called light-independent reactions, CO2 is reduced (via the addition of H atoms) to carbohydrate. These chemical events rely on the electron carrier NADPH and ATP generated by the first set of reactions.光合作用以

5、二氧化碳和水为原材料并经历两步化学反应。第一步，称光反应，水分子分解，氧分子释放，ATP和NADPH形成。此反应需要光能的存在。第二步，称暗反应，二氧化碳被还原成碳水化合物，这步反应依赖电子载体NADPH以及第一步反应产生的ATP。Both sets of reactions take place in chloroplasts. Most of the enzymes and pigments 色素for the lightdependent reactions are embedded 深入的 内含的in the thylakoid类囊体 membrane膜 隔膜 of chloropla

6、sts 叶绿体. The dark reactions take place in the stroma.基质 两步反应都发生在叶绿体中。光反应需要的大部分酶和色素包埋在叶绿体的类囊体膜上。暗反应发生在基质中。How Light Energy Reaches Photosynthetic Cells（光合细胞如何吸收光能的）The energy in light photons in the visible part of the spectrum can be captured by biological molecules to do constructive work. The pigm

7、ent chlorophyll in plant cells absorbs photons within a particular absorption spectrums statement of the amount of light absorbed by chlorophyll at different wavelengths. When light is absorbed it alters the arrangement of electrons in the absorbing molecule. The added energy of the photon boosts th

8、e energy condition of the molecule from a stable state to a less-stable excited state. During the light-dependent reactions of photosynthesis, as the absorbing molecule returns to the ground state, the excess excitation energy is transmitted to other molecules and stored as chemical energy.生物分子能捕获可见

9、光谱中的光能。植物细胞中叶绿素在不同光波下吸收部分吸收光谱。在吸收分子中，光的作用使分子中的电子发生重排。光子的能量激活了分子的能量状态，使其从稳定态进入不稳定的激活态。All photosynthetic organisms contain various classes of chlorophylls and one or more carotenoid (accessory) pigments that also contribute to photosynthesis. Groups of pigment molecules called antenna complexes are p

10、resent on thylakoids. Light striking any one of the pigment molecules is funneled to a special chlorophyll a molecule, termed a reaction-center chlorophyll, which directly participates in photosynthesis. Most photosynthetic organisms possess two types of reaction-center chlorophylls, P680 and P700,

11、each associated with an electron acceptor molecule and an electron donor. These aggregations are known respectively as photosystem (P700) and photosystem (P680).所有的光合作用生物含有不同等级的叶绿素和一个或多个类胡萝卜素（光合作用的辅助色素）。称作天线复合体的色素分子群存在于类囊体中。激活色素分子的光能进入叶绿素反应中心，其直接参与光合作用。大部分光反应细胞器拥有两套反应中心，P680和P700，每个光系统都含有一个电子受体和电子供体

12、。这些集合体就是大家熟识的光合系统和光合系统 。The Light-Dependent Reaction: Converting Solar Energy into Chemical-Bond Energy光反应：光能转化成化学键能The photosystems of the light-dependent reactions are responsible for the packaging of light energy in the chemical compounds ATP and NADPH. This packaging takes place through a series

13、 of oxidation reduction reactions set in motion when light strikes the P680 reaction center in photosystem . In this initial event water molecules are cleaved, oxygen is released, and electrons are donated. These electrons are accepted first by plastoquinone and then by a series of carriers as they

14、descend an electron transport chain. For each four electrons that pass down the chain, two ATPs are formed. The last acceptor in the chain is the P700 reaction center of photosystem . At this point incoming photons boost the energy of the electrons, and they are accepted by ferredoxin. Ferredoxin is

15、 then reoxidized, and the coenzyme NADP+ is reduced to the NADPH. The ATP generated previously and the NADPH then take part in the light independent reactions.光反应的光系统将光能转化成化学复合物ATP和NADPH。当光激活光系统的光反应中心时，通过一系列的氧化还原反应实现能量的传递。反应开始时，水被分解，氧被释放并提供电子。电子首先传递给质体醌，然后通过一系列载体形成的电子传递链。每传递4个电子，形成2个ATP。最后一个受体存在于光反应

16、系统的反应中心里。此处光子激活电子，电子传递给铁氧还蛋白。铁氧还蛋白再氧化，并且辅酶NADP+还原成NADPH。早期产生的ATP和NADPH进入暗反应。The production of ATP from the transport of electrons excited by light energy down an electron transport chain is termed photophosphorylation. The one-way flow of electrons through photosystems II and I is called noncyclic p

17、hotophosphorylation; plants also derive additional ATP through cyclic photophosphorylation, in which some electrons are shunted back through the electron transport chain between photosystems and .由电子传递链偶连产生ATP的过程称为光合磷酸化。通过光合系统流经光合系统的电子路径称非循环式光合磷酸化；植物通过循环式光合磷酸化获得额外的ATP，一些电子在光合系统和之间的电子传递链中回流。The Light

18、-Independent Reactions: Building Carbohydrates暗反应：碳水化合物的形成In the light-independent reactions of photosynthesis, which are driven by ATP and NADPH, C02 is converted to carbohydrate. The reactions are also known as the Calvin-Benson cycle. Atmospheric CO2, is fixed as it reacts with ribulose biphospha

19、te (RuBP), a reaction that is catalyzed by the enzyme ribulose biphosphate carboxylase. The reduction Of C02 to carbohydrate (fructose diphosphate) is completed via several more steps of the cycle. Finally, RUBP is regenerated so that the cycle may continue.由ATP和NADPH驱动的暗反应中，二氧化碳转化成碳水化合物。即卡尔文循环。二磷酸核

20、酮糖固定二氧化碳，由二磷酸核酮糖羧化酶催化。Oxygen: An Inhibitor of photosynthesis（氧：光合作用的抑制因子）High levels of oxygen in plant cells can disrupt photosynthesis and can also cause photorespiration-an inefficient fun of the dark reactions in which 02 is fixed rather than C02 and no carbohydrate is produced.Reprieve from Pho

21、torespiration: The C4 PathwayMost plants are C3 plants; they experience decreased carbohydrate production under hot, dry conditions as a result of the effects of photorespiration. Among C4 plants, however, special leaf anatomy and a unique biochemical pathway enable the plant to thrive in and condit

22、ions. Thus C4 plants lessen photorespiration by carrying out photosynthesis only in cells that are insulated from high levels of CO2. They also possess a novel mechanism for carbon fixation. 大部分植物是碳3植物，在高温干旱条件下，由于光呼吸作用而使碳水化合物的合成降低。而在大多数的碳4植物中，由于叶脉的特殊构造和独特的化学路径使植物依然很茂盛。这是碳固定的一个新机制。课后作业：第一篇阅读材料答案：1B,2

23、A,3A,4D,5C,6cLesson Three（2学时）Cellular Reproduction: Mitosis and MeiosisThe Nucleus and ChromosomesThe cell nucleus is the main repository of genetic information. Within the nucleus are the chromosomes tightly coiled strands of DNA and clusters of associated proteins. Long stretches of the continuou

24、s DNA molecule wind around these clusters of proteins, or histones, forming beadlike complexes known as nucleosomes. More coiling and supercoiling produces a dense chromosome structure. Each long strand of DNA combines with histones and nonhistone proteins to make up the substance chromatin.细胞核是贮藏遗传

25、信息的主要场所。DNA盘绕成螺旋线以及相关的成簇蛋白质。DNA螺旋线缠绕成簇的组蛋白形成珠链状的核小体。这些螺旋和超螺旋形成致密的染色体组结构。每个长链DNA与组蛋白和非组蛋白一起构成染色质物质。A pictorial display of an organisms chromosomes in the coiled, condensed state is known as a karyotype. Karyotype reveal that in most cells all but sex chromosomes are present as two copies, referred to

26、 as homologous pairs. Non-sex chromosomes are called autosomes. Organisms whose cells contain two sets of parental chromosomes are called diploid; those with cells containing a single set of parental chromosomes are called haploid. 染色体致密的超螺旋状态我们称染色体组。除了性染色体外，大多数细胞的染色体组成对出现，称同源染色体对。非性染色体称常染色体。生物细胞含有两

27、套父母本染色体的称二倍体；含有单套染色体的称单倍体。The Cell CycleThe cell cycle is a regular sequence in which the cell grows, prepares for division, and divides to form two daughter cells, each of which then repeats the cycle. Such cycling in effect makes single-celled organisms immortal. Many cells in multicellular organi

28、sms, including animal muscle and nerve cells, either slow the cycle or break out of it altogether.在细胞生长过程中，细胞循环遵循特定程序，分裂准备，分裂成2个子细胞，子细胞再循环。此循环使得单细胞永生。多细胞生物中的许多细胞，包括动物肌肉和神经细胞，要么降低循环速度，要么同时分裂。The normal cell cycle consists of four phases. The first three include G1, the period of normal metabolism; S

29、phase, during which normal synthesis of biological molecules continues, DNA is replicated, and histones are synthesized; and G2, a brief period of metabolism and additional growth. Together the G1, S, and G2 phases are called interphase. The fourth phase of the cell cycle is M phase, the period of m

30、itosis, during which the replicated chromosomes condense and move and the cell divides. It is believed that properties of the cell cytoplasm control the cell cycle, along with external stimulators and inhibitors such as chalones.正常细胞循环由4个时期组成。头三期包括G1,正常新陈代谢；S期,正常新陈代谢同时，DNA复制，组蛋白合成； G2 期，短期的新陈代谢和少许生长

31、。G1, S, 和G2称分裂间期。最后是M期，有丝分裂期，复制的染色体组浓缩，移动并细胞分裂。据称是染色质控制了细胞循环，伴随外部激活因子和抑制因子如抑素。 Mitosis: Partitioning the Hereditary MaterialBiologists divide the mitotic cycle into four phases. At the beginning of prophase 前期 the chromosomes each consist of two highly condensed chromatids attached to each other at

32、a centromere. As prophase ends and metaphase 中期 begins, the condensed 浓缩的 chromosomes become associated with the spindle 纺锤体. Eventually the chromosomes become arranged in a plane (called the metaphase plate) at a right angle to the spindle fibers. Next, during anaphase 后期, the two sister chromatids of each chromosome split, and one from each pair is drawn toward each pole of the cell. During telophase 末期 nuclear envelopes 包膜 begin to form around each set of chromosomes, and division of the cytoplasm takes place.生物学家将有丝分裂划分为4个阶段。分裂前期，高度浓缩的两个染色单体通过着丝粒连接在一起。在分裂前期后期和分裂中期前期，浓缩的染色体与纺