Programme For International Student Assessment Pisa / Sample Science Passage 1: Cloning


Read the newspaper article and answer the questions that follow. 

A copying machine for living beings? 

Without any doubt, if there had been  elections for the animal of the year 1997, 
Dolly would have been the winner! 
Dolly is a Scottish sheep that you see in 5 the photo. But Dolly is not just a simple  sheep. She is a clone of another sheep. 
A clone means: a copy. Cloning means  copying ‘from a single master copy'. 
Scientists succeeded in creating a sheep (Dolly) that is identical to a sheep that  functioned as a ‘master copy'. 

It was the Scottish scientist Ian Wilmut  who designed the ‘copying machine' for  sheep. He took a very small piece from the udder of an adult sheep (sheep 1). 
From that small piece he removed the nucleus, then he transferred the nucleus  into the egg-cell of another (female)  sheep (sheep 2). 
But first he removed from that egg-cell all the material  that would have determined sheep characteristics in a lamb produced from  that egg-cell. Ian Wilmut implanted the manipulated egg-cell of sheep 2 into yet another (female) sheep (sheep 3). Sheep 3  became pregnant and had a lamb: Dolly. 

Some scientists think that within a few  years it will be possible to clone people as  well. But many governments have already 

30 decided to forbid cloning of people by law. 

Source: Tijdschrift van de Eenhoorn Educatief (Brussels Onderwijs Punt): March 1997. 



Which sheep is Dolly identical to?

Sheep 2
Sheep 1
Dolly\'s father
Sheep 3

The part of the udder that was used is described as \'a very small piece\'. From the article text you can work out what is meant by \'a very small piece\'. That \'very small piece\' is

A cell nucleus
A chromosome
A cell
A gene