CAMBRIDGE IELTS 2
PRACTICE TEST 4
READING
READING PASSAGE 3
You should spend about 20 minutes on Questions
27-40 which are based on Reading Passage 3 below
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IN SEARCH OF THE HOLY
GRAIL
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It has been
called the Holy Grail of modern biology. Costing more than £2 billion, it is
the most ambitious scientific project since the Apollo programme that landed
a man on the moon. And it will take longer to accomplish than the lunar
missions, for it will not be complete until early next century. Even before
it is finished, according to those involved, this project should open up new
understanding of, and new treatments for, many of the ailments that afflict
humanity. As a result of the Human Genome Project, there will be new hope of
liberation from the shadows of cancer, heart disease, auto-immune diseases
such as rheumatoid arthritis, and some psychiatric illnesses.
The
objective of the Human Genome Project is simple to state, but audacious in
scope; to map and analyse every single gene within the double helix of
humanity’s DNA1. The project will reveal a new human anatomy – not
the bones, muscles and sinews, but the complete generic blueprint for a human
being. Those working in the Human Genome Project claim that the new genetical
anatomy will transform medicine and reduce human suffering in the
twenty-first century. But others see the future through a darker glass, and
fear that the project may open the door to a world peopled by Frankenstein’s
monsters and disfigured by a new eugenics2.
The genetic
inheritance a baby receives from its parents at the moment of conception
fixes much of its later development, determining characteristics as varied as
whether it will have blue eyes or suffer from a life-threatening illness such
as cystic fibrosis. The human genome is the compendium of all these inherited
genetic instructions. Written out along the double helix of DNA are the
chemical letters of the genetic text. It is an extremely long text, for the
human genome contains more than 3 billion letters. On the printed page it
would fill about 7,000 volumes. Yet, within little more than a decade, the
position of every letter and its relation to its neighbours will have been
tracked down, analysed and recorded.
Considering
how many letters there are in the human genome, nature is an excellent
proof-reader. But sometimes there are mistakes. An error in a single ‘word’ –
a gene – can give rise to the crippling condition of cystic fibrosis, the
commonest genetic disorder among Caucasians. Errors in the genetic recipe for
haemoglobin, the protein that gives blood its characteristic red colour and which
carries oxygen from the lungs to the rest of the body, give rise to the most
common single-gene disorder in the world; thalassemia. More than 4,000 such
single-gene defects are known to afflict humanity. The majority of them are
fatal; the majority of the victims are children.
None of the
single-gene disorders is a disease in the conventional sense, for which it
would be possible to administer a curative drug; the defect is pre-programmed
into every cell of the sufferer’s body. But there is hope of progress. In 1986,
American researchers identified the genetic defect underlying one type of
muscular dystrophy. In 1989 a team of American and Canadian biologists
announced that they had found the site of the gene which, when defective,
gives rise to cystic fibrosis. Indeed not only had they located the gene,
they had analysed the sequence of letters within it and had identifies the
mistake responsible for the condition. At the least, these scientific
advances may offer a way of screening parents who might be at risk of
transmitting a single-gene defect to any children that they conceive.
Foetuses can be tested while in the womb, and if found free of the genetic
defect, the parents will be delivered of a baby free from the disorder.
In the
mid-1980s, the idea gained currency within the scientific world that the
techniques which were successfully deciphering disorder-related genes could
be applied to a larger project; if science can learn the genetic spelling of
cystic fibrosis, why not attempt to find out how to spell ‘human’? Momentum
quickly built up behind the Human Genome Project and its objective of ‘sequencing’
the entire genome – writing out all the letters in their correct order.
But the consequences
of the Human Genome Project go far beyond a narrow focus on disease. Some of
its supporters have made claims of great extravagance – that the Project will
bring us to understand, at the most fundamental level, what it is to be
human. Yet many people are concerned that such an emphasis on humanity’s
genetic constitution may distort our sense of values, and lead us to forget
that human life is more than just the expression of a genetic program written
in the chemistry of DNA.
If properly
applied. The new knowledge generated by the Human Genome Project may free
humanity from the terrible scourge of diverse diseases. But if the new
knowledge is not used wisely, it also holds the threat of creating new forms
of discrimination and new methods of oppression. Many characteristics, such
as height and intelligence, result not from the action of genes and the
environment. What would be the implication if humanity were to understand,
with precision, the genetic constitution which, given the same environment,
will predispose one person towards a higher intelligence than another
individual whose genes were differently shuffled?
Once before
in this century, the relentless curiosity of scientific researchers brought
to light forces of nature in the power of the atom, the mastery of which has
shaped the destiny of nations and overshadowed all our lives. The Human
Genome Project holds the promise that, ultimately, we may be able to alter
our genetic inheritance if we so choose. But there is the central moral
problem; how can we ensure that when we choose, we choose correctly? That such
a potential is a promise and not a threat? We need only look at the past to
understand the danger.
Glossary
1DNA Deoxyribonucleic acid,
molecules responsible for the transference of genetic characteristics.
2eugenics The science of improving the
qualities of the human race, especially the careful selection of parents
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Questions 27-32
Complete the sentences below (Questions
27-32) with words taken from Reading Passage 3.
Use NO MORE THAN THREE WORDS OR A NUMBER
for each answer.
Write your answers in boxes 27-32 on your
answer sheet.
Example Answer
The passage compares the genetic instructions in DNA to chemical
letters
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27
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The passage
compares the Project in scale to the __________________________________.
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28
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The possible
completion date of the Project is __________________________________.
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29
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To write out
the human genome on paper would require __________________________________
books.
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30
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A genetic
problem cannot be treated with drugs because strictly speaking it is not a ____________________.
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31
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Research
into genetic defects had its first success in the discovery of the cause of
one form of __________________________________.
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32
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Thee second
success of research into genetic defects was to find the cause of ___________________________.
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Questions 33-40
Classify the
following statements as representing
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A
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The
writer’s fears about the Human Genome Project
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B
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other
people’s fears about the Project reported by the writer
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C
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The
writer’s reporting of facts about the Project
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D
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the
writer’s reporting of the long-term hopes for the Project
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Write
the appropriate letters A-D in boxes 33-40 on your answer sheet.
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33
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The Project will provide a new
understanding of major diseases.
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34
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All the components which make up DNA
are to be recorded and studied.
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35
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Genetic monsters may be created.
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36
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The correct order and inter-relation of
all genetic data in all DNA will be mapped.
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37
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Parents will no longer worry about
giving birth to defective offspring.
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38
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Being ‘human’ may be defined solely in
terms of describable physical data.
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39
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People may be discriminated against in
new ways.
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40
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From past experience humans may not use
this new knowledge wisely.
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ANSWER
KEY
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