Book 8 Unit 2 Cloning

   short time.
    a.how     b. that      c. when    d. what
10. --- can i help you?
   --- yes, do you know ____?
     a. when comes the bus           b. when will come the bus
     c. when does the bus come        d. when the bus comes

   
教師參考答案
book 8 unit 2 cloning
warming up and pre-reading

ⅰ. 背景閱讀
cloning is the technique of producing a genetically identical duplicate of an organism. a clone is said to be all descendants derived asexually from a single individual, as by cuttings, bulbs, by fission, by mitosis, or by parthenogenesis reproduction. it sounds very different and complicated to us.
in fact, in our daily life, this happens often. for example, gardeners take cuttings from growing plants to make new ones. you often see that your mother picks a small branch from a growing plant to make a new one. if she likes this kind of flowers, she can do cloning. cloning also happens in animals or human beings when twins identical in sex and appearance are produced from the same original egg. the fact is that cloning plants is straightforward but the cloning of animals is more complicated.
 the possibility of human cloning, raised when scottish scientists at roslin institute created the much-celebrated sheep "dolly", aroused worldwide interest and concern because of its scientific and ethical implications. she was the first mammal to be cloned from adult dna taken from an adult cell. previously, animals had only been cloned using embryo cells which already have the potential to become a complete embryo in its own right. the big breakthrough with dolly was to make a clone from an ordinary, adult cell − in this case from a female goat’s udder.

1. fill in the blanks according to the passage.
1) the definition of cloning
cloning is a way/technique of producing a genetically identical duplicate of an animal or a plant. it happens both in  plants  and in animals. they can be cloned by themselves or humans. the former is natural  while the latter is man-made.
2) how does dolly differ from other sheep?
she was cloned by humans while the others were born naturally.
so, dolly was a cloned sheep.

2. discuss the following questions.
1). can you see any cloning happen in our daily life?