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That there are other molecules in the lipid bilayer and they're important for cells getting information or getting molecules from outside.
还有一些其它分子在这个脂质双分子层上,它们对于细胞接收信息,和接受外来分子十分重要
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The plants can be deficient in certain things, especially fat soluble vitamins that come from meat and from essential amino acids.
植物中缺乏某些物质,特别是脂溶性维生素,那些只能从肉类和必需氨基酸中获得
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Steroids are small molecules - much smaller than proteins - smaller molecules that tend to be hydrophobic or lipid soluble.
类固醇是小分子物质,比蛋白质小得多,这类小分子是非水溶性的,或者说是脂溶性的
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But you know, sometimes what seems to be the virtuous may not necessarily be, so that would be an example.
但是现在你们知道了,有时候看起来低脂的食物并不一定低脂,这是个很好的例子
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But then they can also be toxic if taken in too large of amounts because the body does store them.
但如果摄入过量也会中毒,因为机体储存的脂溶性维生素也会过量
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So most of the lipids, which make up cell membranes in your body are of this category of phospholipids.
大部分脂类,那些在你体内构成细胞膜的脂类,都属于磷脂类
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I've already mentioned many times that the lipid bilayer, the cell membrane, isn't just a lipid bilayer.
我已经讲过很多遍这个脂质双分子层了,细胞膜它不只是一个脂质双分子层
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There's lipid chains in between so cell membranes are lipid rich layers that can exist in water.
脂质链在两者中间,所以细胞膜是富含脂类的膜层,并可以稳定存在于水中
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The lipids will form a bi-layer where the water soluble part of the lipid points out of this layer and the oily part points in.
脂质会形成双层膜,水溶性部分朝向膜层外,而脂溶性的部分朝向双层膜内部
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Cosmetic surgery - you gave two examples, one was Botox and the other was liposuction.
整容手术,你告诉我们两个例子,一个是肉毒杆菌素,另一个是抽脂手术
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Now some people can some people may be turned off by those high fat foods.
现在有些人可以,有些人可能开始抗拒高脂食品
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Doesn't it make sense then that being sedentary and seeking out high fat, high sugar, high calorie foods has become a priority woven into our biology?
我们的生物学天性,即静养至上,寻求高脂高糖高热量的饮食,是有一定的道理的
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Alright, how many of you would say a low fat diet is best?
好了,多少人支持低脂饮食
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Okay, fat is number two, so you guys are good so far.
好的 高脂是第二个,目前为止 你们都回答得很好
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You want to look at the effect of a low fat diet.
你想要知道低脂饮食的效果如何
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I'll talk about biological membranes and lipids and how they're assembled.
我会讲到生物膜和脂质,及它们是如何组装成质膜的
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Special lipids that do this are called cationic lipids.
比如说阳离子脂质体
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We'll see why they have to separate that in a minute, but they do that these lipid bi-layers solve that problem for them and they're self-assembled structures from these molecules called phospholipids.
我们马上会讲到为什么要把它们隔离开,脂质双层膜解决了这个问题,而这些自主装结构,就是由磷脂分子组成的
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Well instead of forming droplets like fat they arrange in a very particular way, they form these structures that are called self-assembled structures because they occur naturally, because of properties of the lipids.
它们不是像脂肪一样形成液滴,而会细致地排列起来,它们形成的结构名为,自组装结构,因为它们能够自然生成,这归功于这种脂质的特性
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In any event, the saturated fats that are in these kinds of foods tend to be in the things that you associate with fatty foods like high fat meat, whole milk, etc., have a bad impact.
不论如何,这些食物中的饱和脂肪,正是你们通常称为高脂食品,如肥肉,全脂牛奶等,都是有害的
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Because if you were unfettered by all those environmental things that make people eat different kinds of foods, most of you would probably like the high fat, high sugar foods better; most of you probably still do.
因为如果你可以不受这些环境因素影响,摆脱让人们吃各种不同的食物的外因,大部分人都会更喜欢高脂食品,或者高糖食品,你们中的大部分人可能依然如此
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As I mentioned in the earlier class, most of you would probably rather have some high fat food like French fries or ice cream, or some type of a dessert than have cauliflower or have broccoli or have brussel sprouts.
就像我前面提到的,你们大部分人都宁愿,食用高脂食品,诸如炸薯条或冰激凌,或者一些甜点,而不是花椰菜,西兰花或是抱子甘蓝
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I do want to talk about one important subject which you might not have thought too much about and that's lipids, because lipids are so important to the structure of the body because they make up the membranes that form the cells that are the fundamental units.
我的确想要讨论一个重要的主题,这个主题也许你们都没有深入思考过,那就是关于脂类的问题,脂类对身体结构形成十分重要,它是组成细胞膜的基本单位,而细胞膜能够维持细胞形态
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Because humans want to eat a lot, they want to bank their calories, they want to seek out foods that are high in sugar, fat, and variety, and if those are available then they're going to be eaten and we've got problems.
人们想要多吃,需要储存能量,人们一直在寻找高糖高脂的食物,如果找到,他们就会全部吃掉,然后我们就有麻烦了
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There can be a supply of them, a storehouse of them that can build up in the body, and so day-to-day fluctuations become less of a problem with fat soluble then water soluble vitamins, because the body can go grab them from a storage depot, if you will.
从而在体内建立起一个供应源,一个脂溶性维生素仓库,这样一来,相比起水溶性维生素,脂溶性维生素的浓度不会每天剧烈波动,因为机体可以任意取用体内的储存
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So tens or hundreds of millions of dollars would go into a study like this by the time it was completed, money that could have been used for other things, to test whether eating a low fat diet would reduce risk for breast cancer.
数以百万计的美元,投入到这样的研究,当研究结束时,本可以用来做其他事情的钱,被用来检测是否低脂膳食,可降低患乳腺癌风险
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On the side over here shows a cell membrane and so this is outside the cell above it, and this is inside the cell below, and this is the lipid bilayer that separates the outside of the cell from the inside of the cell.
这边这个表示细胞膜,它的上面代表细胞外部,下面代表细胞内部,这个是脂质双分子层,将细胞内外分开
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The water soluble vitamins tend to be used more immediately by the body not stored and excreted through the urine if consumed in excess, so the body can tolerate more variation in intake of these before you start getting toxicity than is the case with the vitamins on the right.
而水溶性维生素往往都立刻被身体所利用,不会被机体储藏,过剩部分由尿液排出,因此机体耐受过量水溶性维生素的能力,相比起右边这栏里的脂溶性维生素,可是要强得多了
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I talked about just not using viruses but using plasmid DNA together with lipids and that's another strategy for gene therapy.
这一部分我们不仅讲了病毒的应用,也讲了利用脂质体包裹的质粒DNA,基因治疗还有其它的策略
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They're lipids but they also have a charged portion, a positively charged portion which interacts with DNA.
它虽然是脂类,但一部分带有电荷,其带有的正电荷将与DNA产生静电作用
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