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It's one of the only compounds, there's only I think three, where the density actually goes down when it freezes.
它是我见过的，唯一一个，在降温时密度下降的化合物。
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But this is a compound, right, it has some non-zero heat of formation from the elements. So is water, right?
但这是种化合物，对吧？,它具有非零的生成热,水也是一样，对吧？
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And you would expect that that would be a much stabler compound because, instead of plus one attracting plus one, now you have plus two attracting minus two.
可以预见,这将会是更稳定的化合物，因为不再是一价正离子吸引一价负离子，而是二价正离子吸引二价负离子。
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You got cholesterol, sodium, carbohydrate here, broken down as fiber and sugars, and that's very helpful information to know.
这里还有胆固醇,钠及碳水化合物含量,碳水化合物又被细分为膳食纤维和糖,这也是很有用的信息
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And what it's used is to convert one type of group, what's called a carboxylic acid into another type of very reactive intermediate, which is called an acid chloride.
它被用来将一类被称作羧酸的化合物，转化成另外一类活性很高的反应中间体,也就是酰氯。
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Basically, you're introducing this gene into cells that when you give the right inactive drug that will cause the cell to make chemicals that kill it.
概括来说,当你把这个自杀基因导入,含有特定未激活药物的细胞时,二者作用就使细胞生成了,可以杀死自己的化合物
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I'll talk today about protein and then next week, or next class, we'll talk in more detail about carbohydrate and fat.
我们会在今天讨论蛋白质,下节课进一步解释碳水化合物和脂肪
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Maybe you're not looking at a reaction, but you've got some new compound, and you're looking at it go from liquid to solid or to gas.
也许你研究的不是一个反应,但你得到了一种新的化合物,你看着它从液体变成了固体或气体。
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Well, I need to write the reaction that forms that compound from it's elements, right?
我需要写出从元素单质生成,这种化合物的反应，对吧？
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Atoms of different elements combine in simple whole number ratios to form compounds.
不同元素的原子,以简单的整数比化合成化合物。
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Just so that we are clear, this is the bond in this compound.
所以我们明白，这是化合物中的共价键。
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Today we're going to talk about the two big ones that people are usually concerned with: carbohydrates and fat.
今天我们将讨论人们关心的两个大问题,碳水化合物和脂肪
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The word "carbohydrate," as you might imagine, if you ever thought to break it down means the combination of carbon and water.
碳水化合物这个词,如你所想,如果你把它进行拆分的话,就是碳和水的结合物
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But you do, in fact, have to worry about long-term exposure, cyanide poisoning in terms of long-term effects in certain populations that do get the bulk of their carbohydrates from this root, from the root of the Cassava plant.
但是你确实，不得不担心长时间的接触，氰化物的慢性中毒会对,从木薯根中获取大部分,碳水化合物的部分人群产生影响。
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As I mentioned before, fat has twice the calories per unit weight as protein and carbohydrate.
如我之前所说,单位重量中脂肪的热量含量,是蛋白质和碳水化合物的两倍
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Do they eat a lot of carbs, a lot of fat, whatever they happen to eat.
是否摄入过量的碳水化合物和脂肪
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So as I said, we'll talk about protein this week a little bit, and then fats and carbs next week.
我说过,我们这周会讨论蛋白质,下周是脂肪和碳水化合物
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Fat has twice the calories per unit weight that protein or carbohydrate sugar has, as a consequence, has the greatest survival value.
单位重量中脂肪的热量含量,是蛋白质和碳水化合物的两倍,因此,脂肪才是最能维持生存的物质
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What about sources of protein, that and carbohydrate for you, and how do those look and where are you getting those from?
那蛋白质的来源呢,还有碳水化合物,这些都长什么样,你从何摄入这些元素
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And for any of the other compounds. So in other words, by defining that reference state, we can then figure out or measure heats of formation of a vast number of compounds.
对吧？对于任何其他的,化合物也是一样，所以换句话讲，定义了这个参考状态,我们就能算出或测量许多。
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And when a compound is decomposed, the atoms are recovered unchanged.
当一个化合物被分解的时候，原子有恢复原来未曾改变的面貌。
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The macro nutrients are the big constituents of food, that's protein, carbohydrate, and fat.
大量营养素是食物重要组成来源,即蛋白质,碳水化合物和脂肪
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Then the polysaccharides are the complex carbohydrates, and that's starch, glycogen, and cellulose.
多糖则是复杂的碳水化合物,淀粉,糖原,以及纤维素都是多糖
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Electrolysis of water, catalytic decomposition of hydrocarbons?
电解水，催化分解碳氢化合物？
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The macronutrients, protein, carbohydrate and fat; the micronutrients vitamins, minerals and water.
大量营养素,蛋白质,碳水化合物和脂肪,微量营养素,维生素,矿物质和水
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We can tabulate them. We can know them, and then when we have reactions that inter-convert different compounds, we can calculate the heat of reaction is just the difference between the heat of formation of the reactants, and the heat of formation of the products, right.
种化合物的生成热，可以把它们列成表,可以认知它们，而当我们要处理，在不同化合物间转变的反应时,我们只要计算反应物和,生成物的生成热之间的不同,就能计算出反应热。
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And so the amount of protein in a diet, from diet plan to diet plan, doesn't vary as much as the recommendations that these popular diets give you for fat and carbohydrate.
在不同食谱中,对于蛋白摄入量的差异,远远不如对脂肪,和碳水化合物的摄入量的差异那样大
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Carbohydrate has really shifted, and so people are eating more calories from carbohydrate before, sugars primarily, and that is coming primarily from added sugar, or that's at least one of the primary contributors.
碳水化合物也有明显的变化,比前人更多的从碳水化合物中摄取热量,以糖类为主,也就是说主要是添加糖类的食物,至少这是主要的来源之一
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Let's start with carbohydrates. Sugars, in other words.
我们从碳水化合物,即糖类开始
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another thing that you'd find if you looked inside the axon terminals of any of these pre-synaptic membranes, you'd find lots of vesicles or some membrane bound compartments that contain special chemicals called neurotransmitters.
如果你仔细观察,突触前膜的轴突末梢内部,你会发现很多小泡,即膜包被的结构,包含有称为神经递质的特殊化合物
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