文档介绍：英语课标教学课件
选修8
Unit 2
Cloning
Who is Yang Yang?
Yang Yang is China’s first essfully cloned sheep. Yang Yang was born in 2000, and has just had its 14th birthday. It’s the world’s longest-living cloned sheep.
1. To learn some basic information about cloning
2. To know the difference between a natural clone and a man-made clone
A clone is an animal or plant produced
naturally or artificially from the cells of
another animal or plant and is exactly
the same as it.
Cloning is a way of making an exact
copy of another animal or plant.
The clone has the same DNA as the
parent.
What’s cloning?
Sounds Reasonable?
There are different types of cloning, and cloning technologies can be used for other purposes besides producing the ic
twin of anism. The three types
of cloning technologies are:
(1) binant DNA technology or DNA
cloning(基因重组克隆技术)
(2) reproductive cloning(生殖性克隆)
(3) therapeutic cloning
(治疗性克隆)
克隆一词是英文单词clone的音译,作为名词,clone通常被意译为无性繁殖系。同一克隆的所有成员的遗传构成是完全相同的,例外仅见于有突变发生时。自然界早已存在天然植物、动物和微生物的克隆。
人们开始探索用人工的方法来生产高等动物克隆。这样,克隆一词就开始被用作动词,指人工培育克隆动物这一动作。
目前,生产哺乳动物克隆的方法主要
有胚胎分割和细胞核移植两种。克隆羊
“多莉”,以及其后各国科学家培育的各种
克隆动物,采用的都是细胞核移植技术。
所谓细胞核移植,是指将不同发育时期的胚胎或成体动物的细胞核,经显微手术和细胞融合方法移植到去核卵母细胞中,重新组成胚胎并使之发育成熟的过程。由于细胞核移植是产生克隆动物的有效方法,故人们往往把它称为动物克隆技术。
Twins
Natural clone
Dolly the sheep
Man-made clone
In pairs, look at these pictures and discuss which ones are natural clones and which ones are man-made. Think about how they differ.