大学英语

快速阅读 What are genetically modified GM foods?

Man has been \"genetically modifying\" everything from food to dogs for many centuries; but in the past, the only tool has beenselective breeding.For example, if you wanted to create a breed of corn with resistance to a certain fungus, you would plant a plot of corn and see how individual plants did with the fungus.Then you would take seeds from the plants that did well, plant them, look at their performance against the fungus… and so on over the years until you had created a strain of corn plant that had very high resistance to the fungus in question.

Using selective breeding techniques, people have created everything from variegated roses to giant pumpkins to strains of wheat with twice the yield and very high disease tolerance.In the same way, you can take chickens, analyze their eggs and find chickens with eggs that contain le cholesterol.Then you can breed them to create a strain of low-cholesterol chickens.You can select on any detectable trait and selectively breed members of the species that do well on that trait.

Genetic engineering techniques now allow scientists to insert specific genes into a plant or animal without having to go through the trial-and-error proce of selective breeding.Genetic engineering is therefore extremely rapid compared to selective breeding.With genetic engineering, you can also cro species very easily (for example, you can create a plant that produces human insulin).You can read the article How Cells Work to learn about DNA, genes and gene splicing.The techniques are now standard and genes can be spliced very easily.

There are a variety of techniques used to modify plants and animals through genetic engineering.For example, there is a widely used herbicide called Roundup, made by Monsanto.Roundup kills any plant that it touches.Monsanto has genetically modified soybeans and other crop plants to create \"Roundup Ready\" strains that are not affected by Roundup.By planting Roundup Ready seeds, a farmer can control weeds by spraying Roundup right over the crop.The crop completely ignores the herbicide, but the weeds are eliminated.Roundup Ready seeds reduce production costs and increase yield, so food becomes le expensive.Other scientists have inserted genes that produce a natural insecticide into corn plants to eliminate damage from corn borers, and a variety of anti-fungal genes can be inserted as well.The list goes on and on -- there really is no limit to what can be done.

转基因转基因食品是什么?

男子“基因改造”从食物到许多世纪的狗;但在过去,唯一的工具beenselective繁殖。例如,如果你想创建一个玉米品种抗某种真菌,你会开辟出一块玉米,看看株真菌。然后你将种子的植物表现不错,工厂,看看他们的表现对真菌…等等这些年来,直到您已经创建了一个应变非常高的玉米植株抵抗真菌的问题。

通过选择育种技术,人们创造了一切,从玫瑰组合巨型南瓜品种的小麦产量和非常高的疾病公差的两倍。同样地,你可以把鸡,分析他们的蛋和鸡鸡蛋含有胆固醇。然后你就可以繁殖出的低胆固醇鸡。你可以选择在任何检测特征和选择性繁殖的物种成员做好特质。

基因工程技术现在允许科学家将特定基因插入植物或动物,而无需通过选择育种的试错过程。因此,基因工程是极其快速的选择育种,基因工程相比,你也可以很轻易跨越物种(例如,您可以创建一个工厂,生产人胰岛素)。你可以阅读这篇文章细胞如何工作了解DNA,基因和基因剪接。现在的技术标准和基因很容易可以拼接。

有各种各样的方法来修改通过基因工程植物和动物。例如,有一个广泛使用的除草剂叫农达,由孟山都。综述杀死任何植物,它触动。孟山都转基因大豆和其他农作物创造“农达”压力,不受综述。通过种植抗农达种子,农民可以通过喷洒控制杂草集拢在作物。作物完全忽略了除草剂,但杂草消除。抗农达种子降低生产成本,提高产量,所以食物变得更便宜。其他科学家基因产生天然杀虫剂插入玉米植物从玉米螟虫,消除损伤和各种抗真菌基因也可以插入。这样的例子不胜枚举,——实际上是没有限制的可以做什么。

GE Agriculture and genetic pollution

这篇没有

综合训练

两篇都没有

大学英语

大学英语

大学英语

英语大学

大学英语

大学英语

大学英语1

大学英语演讲稿大学英语演讲稿大学英语演讲稿大学英语演讲稿

大学英语模拟题

《大学英语》教学大纲

《大学英语.doc》

将本文的Word文档下载到电脑，方便收藏和打印

推荐度：

点击下载文档