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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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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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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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We talked last time about extracellular matrix and this complex protein-carbohydrate gel that surrounds all cells.
我们上次谈到过的细胞外基质,是一种蛋白和碳水化合物的复合物胶冻,它环绕在细胞周围
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And from that, then you can look at enthalpies of reaction for countless numbers of reactions, right.
很多很多种化合物,利用这些你就可以研究,不计其数的反应的反应焓。
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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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They're the magic nutrient books: carbohydrates, fat, whatever it happens to be, that's one theme you could follow.
它们是些神奇的营养学书籍,碳水化合物,脂肪,或者其它东西,都可以成为著书的主题
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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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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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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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So that's a good start for us putting together a skeletal structure for this compound here.
因此这对我们画这个化合物的,骨架结构来说是个好的开始。
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So I show that here, so in green, you have what's called a carboxcylic acid group, a c o o h, which gets converted by s o c l 2 to a c double bond o c l or an acid chloride.
我在这里用绿色表示，我们所说的羧酸族化合物，碳，氧，氧，氢，它被亚硫酰氯转化为,一个碳氧双键与碳氯单键组成的酰氯。
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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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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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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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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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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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If you look at sources of these different carbohydrates, the glucose comes from fruit.
如果你研究这些不同碳水化合物的出处,水果中含有葡萄糖
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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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But in terms of drugs that don't look like maybe this compound was used in the synthesis, many of them might have used thionyl chloride, because it generates such a nice reactive intermediate that you can go on and make a bunch of different compounds from that intermediate.
但是对于药物来说,它们可能跟合成过程中用到的这种化合物并不相像，很多药物的制造过程中都会用到亚硫酰氯，因为它能产生活性如此之高的反应中间体,以至于你可以继续利用反应中间体,来制造一堆不同类型的化合物。
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So, a natural product is something that is made by nature, and often natural products, whether it comes from a plant or a marine organism have some really good, useful properties. And so, one particular compound has anti-tumor properties. So, again, along this line of cancer research.
天然产物是在自然界中生成的,通常一个天然产物，不管是来自植物或者海洋生物,都有些非常好非常实用的性质，其中的一个特殊的化合物,可以治疗癌症,再一次我们又来到癌症研究上。
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So something about fat is driving people and as I'll explain in a subsequent lecture, What would it be about fat that makes it more reinforcing then protein or carbohydrate?
至于脂肪如何为人们供能,我会在以后的课上解释这点,为什么脂肪比蛋白质或碳水化合物,更能让机体变强
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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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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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