生物与制药工程专业英语第二单元翻译

Biologists and chemists divide compounds into two principal classes, inorganic and organic. Inorganic compounds are defined as molecules, usually small, that typically lack carbon and in which ionic bonds may play an important role. Inorganic compounds include water, oxygen, carbon dioxide, and many salts, acids, and bases.

生物学家和化学家分裂成两个主要种类化合物、无机和有机。无机化合物被定义为分子,通常小,通常缺乏的碳离子束缚,那么它就能起到重要的作用。无机化合物包括水、氧气、二氧化碳和许多盐、酸、和根据地。

All living organisms require a wide variety of inorganic compounds for growth, repair, maintenance, and reproduction. Water is one of the most important, as well as one of the rmost abundant, of these compounds, and it is particularly vital to microorganisms. Outside the cell, nutrients are dissolved in water, which facilitates their passage through cell membranes. And inside the cell , water is the medium for most chemical reactions. In fact, water is by far the most abundant component of almost all living cells. Water makes up 5% to 95% or more of each cell, the average being between 65% and 75%. Simply stated, no organism can survive without water 所有生物体需要多种无机化合物的增长、维修、维护、和繁衍。水是其中一个最重要的、也是最丰富的,这类化合物,这是特别至关重要,微生物。细胞外,营养溶解在水中,有利于他们通过细胞膜。和进入细胞,水介质对大多数化学反应。事实上,水是迄今为止最丰富的组件几乎所有的活细胞。水产生的5% ~ 95%或更多的每一个细胞,平均在65%和75%之间。简单的说,没有生物能生还,没有水。

Water has structural and chemical properties that make it particularly suitable for its role in living cells. As we discussed, the total charge on the water molecule is neutral, but the Oxygen region of the molecule has a slightly negative charge and the hydrogen region has a slightly positive charge. Any molecule having such an unequal distribution of charges is called a polar molecule. The polar nature of water gives it four characteristics that make it a useful medium for living cells

水具有的结构和化学特性使得其尤为适合在活细胞中发挥作用。像我们讨论过的一样,总金额在水分子是中立的,但氧区域的分子都有稍微否定的电荷和氢地区稍微正电荷。有这样一个任何分子分配不均等的指控被称为一个极性分子。极地自然的水给它有四个特点,使它成为一个有用的活细胞中。

First, every water molecule is capable of forming four hydrogen bonds with nearby water molecules. This property results in a strong attraction between water molecules. Because of this strong attraction, a great deal of heat is required to separate water molecules from each other to form water vapor, thus, water has a relatively high boiling point (1OO℃). Since water has such a high boiling point, it exists in the liquid state on most of the earth's surface, Furthermore, the hydrogen bonding between water molecules affects the density of water, depending on whether it occurs as ice or a liquid. for example, the hydrogen bonds in the crystalline structure of water (ice) make it more spacious. As s result，ice has fewer molecules than an equal volume of liquid water. This makes its crystalline structure less dense than an equal olume of liquid water.this makes its crystalline strucrure less dense than liquid water. It is for this reason that ice floats and can serve as an insulating layer on the surfaces of lakes and streams that harbor living organisms.

首先,每个水分子的氢键能力四个形成与附近的水分子。这个属性导致水分子间有强烈的吸引力。因为这个强烈的吸引力,大量的热被要求从彼此分开的水分子形成的水蒸气,因此,水有一个相对高沸点(1 OO℃)。由于水有这样一个高沸点,它存在于液体状态对大部分的地球

表面,此外,水分子间的氢键的密度与水的影响,取决于它是冰或液体。例如,氢键在水晶结构水(冰)使它更宽敞。结果作为年代,ice已经比少与等体积分子液态水。这使其晶体结构体积密度要小于同等的液态水。这使其水晶全部的密度要小于液态水。正是因为这一原因,冰漂浮的,也可以作为隔热层表面的湖泊和溪流滋生的活的有机体。

Second,the polarity of water makes it an excellent disolving medium or solvent.many

polar substances dissociate (separate) into individual molecules in water-that is, dissolve-because the negative part of the water molecule is attracted to the positive part of the molecules in the solute (dissolying substance) , and the positive part of the water molecules is attracted to the negative part of solute molecules. Substances (such as salts) that are composed of atoms (or groups of atoms) held together by ionic bonds tend to dissociate into separate cations and anions in water. Thus, the polarity of water allows molecules of many different substances to separate and become surrounded by water molecules.

第二,极性的水使它成为一个优秀的disolving中型或solvent.many

极性物质(独立)游离water-that中的个别分子,dissolve-because消极部分的水分子被吸引到积极的分子的一部分溶质(dissolying物质),积极的部分水分子被你吸引溶质分子的消极作用。物质(如盐)组成的原子(或群体中的原子)通过离子债券维系在一起的倾向于分开成单独的阳离子和阴离子在水里。因此,水分子的极性允许许多不同的物质分离,成为水分子包围。Third, polarity accounts for water's characteristic role as a reactant or product in many chemical reactions. Its polaritv facilitates the splitting and rejoining of hydrogen (H+ ) and hydroxide (OH ) ions. Water is a key reactant in the digestive processes of organisms, whereby larger molecules are broken down into smaller ones. Water molecules are also involved in synthetic reactions--water is an important source of the hydrogen and oxygen that are incorporated into numerous organic compounds in living cells.

第三,极性占水的特性作为反应物或产品在许多化学反应。它有利于分裂和重新polaritv氢(H +)和氢离子(哦)。水是一个关键的反应物在消化过程的有机体,因此更大的分子分解成较小的分子。水分子也参与——水是合成反应的重要来源,氢气和氧气纳入许多有机化合物在活体细胞。

Finally, the relatively strong hydrogen bonding between water molecules makes water an excellent temperature buffer, A given quantity of water requires a great gain of heat to increase its temperature and a great loss of heat to decrease its temperature, as compared with many other substances. Normally, heat absorption by molecules increases their kinetic energy and thus increases their rate of motion and their reactivity. In water, however, heat absorption first breaks hydrogen bonds rather than increasing the rate of motion. Therefore. much more heat must be applied to raise the temperature of water than to raise the temperature of a nonhydrogen-bonded liquid. The reverse is true as water cools. Thus, water more easily maintains a constant temperat

最后,较强的水分子间的氢键使水成为优秀的温度缓冲区,给定数量的水需要一个重大收获的热增加它的温度和一个伟大的热量损失降低温度,相比而言,许多其他的物质。正常情况下,由分子吸收热量增加,从而增加动能的运动速度和反应。在水里,然而,第一个打破氢键吸收热量的速度,而不是增加运动。因此。更多的热量必须应用水的温度升高的温度升高一个nonhydrogen-bonded液体。事实正相反作为冷却水。因此,水更容易建立保持不变

when inorganic salts such as sodium chloride (NaCl) are dissolved in water, they undergo dissociation, or ionization. That is, they break apart into ions. Substances called acids and bases show similar behavior.

当无机盐如氯化钠(盐)溶解在水中,他们经历了分离、或游离。也就是说,他们分裂成离子。物质称为酸和碱显示类似的行为。

An acid can be defined as a substance that dissociates into one or more hydrogen ions (H+ ) and one or more negative ions (anions). Thus, an acid can also be defined as s proton CH+ ) donor. A base dissociates into one or more positive ions (cations) plus on or more negatively charged hydroxide ions (OH- ) that can accept, or combine with, protons. Thus, sodium hydroxide (NaOH) is a base because it dissociates to release hydroxide ions, which have a strong attraction for protons and are among the most important proton acceptors. A salt is a substance that dissociates in water into cations and anions, neither of which is H or OH

酸可以被定义为一种物质dissociates成一个或多个氢离子(H +)和一个或多个负离子(阴)。因此,一个酸也可以被定义为s质子CH +)捐献者。基地dissociates成一个或多个正离子(阳离子)加上或更多的带负电荷的氢离子(哦-),可以接受,或者结合、质子。因此,氢氧化钠(氢氧化钠)是一个基地,因为它dissociates氢离子的释放,这有一个很大的吸引力,为质子质子中最重要的杂质。盐是一种物质dissociates阴离子在水变成阳离子,这两者都是H或哦