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The Double Helix

S U M M A R Y

ames Watson’s account of how he and fellow scientist
Francis Crick discovered the structure of DNA is a famous
piece of popular science writing. There is as much about

the personalities of the scientists involved in the momentous race
that finally identified the double helix as there is about proteins
and crystallography. Non-scientists can enjoy his story of human
achievement and weakness as much as readers with a science
background.

The events of the story take place over only three years, from

1950 to 1953. It begins in the cold north of Copenhagen, with
Watson’s arrival in Europe in search of a career. Various branches
of science failed to interest him and he is quite honest about his
unfocused early working life. Knowing that his real interest lay in
understanding genes, he moved to Cambridge University in
England, where he immediately teamed up with the excitable
Francis Crick. Crick’s loud voice gave many of his colleagues a
continuous headache.

Advances in understanding DNA were being made by a brilliant

American scientist, Linus Pauling, across the Atlantic. Watson and
Crick know that time is short and that they are in a race with
Pauling to find the structure of DNA. The middle section of the
book deals with their attempt to understand DNA by using
models. They can’t persuade any other scientists that theirs is the
right way, however, and after a failed first attempt, their work on
DNA stops. Having upset all the people who could have helped
them, it seems that Crick and Watson will never make it. Life at
Cambridge continues and Watson has plenty to say about
accommodation and meals in Cambridge colleges.

In the final part of the book, the race to unravel DNA gets hotter.

Linus Pauling at Cal Tech in Pasadena, in California, is nearly
there. He publishes a paper, but too soon. Watson and Crick
immediately realize that he has made a fundamental error. Their
desire to win the race sends them running back to their DNA ideas
and models. Watson recounts how they arrive at the answer,
finally winning the support of their colleagues as they get there.
The story ends with Watson, aged only 25, and Crick, announcing
to the world that they have uncovered the nature of life.

James Watson was born in 1928 in Chicago in the United States.
He studied first at the University of Chicago and then took his
PhD at the University of Indiana, winning his doctorate when he
was still only 22. The story of his career from 1950 to 1953 and
the discovery of the double helix is told in this book.

After receiving the Nobel Prize in 1962, Watson moved from

Cambridge to Cal Tech in California where he worked until 1968.
The second volume of his autobiography, Genes, Girls and
Gamow, was published in 2001 and talks in detail about these
years. It also deals with his bumpy love life, ending with his
marriage to his present wife, Liz.

The illustration on the front cover of this Penguin Reader is of a
double helix - the structure of a DNA molecule. A helix is a spiral.
A double helix consists of two parallel spirals. If you unwound a
DNA molecule, it would be a metre long. DNA molecules carry all
the information about a living organism, in other words, the secret

of life. They carry this information in genes. In humans, each DNA
molecule contains about 1,000 genes. Each gene has a unique
code which is related to a specific characteristic, such as hair
colour, eye colour, blood type, intelligence.

It was several decades after Crick and Watson’s great discovery

that the potential of DNA came to be recognized. Would they have
predicted what would follow? Today the scientific press is full of
advances in medicine, agriculture and industry which use DNA. It
is also widely used in criminal investigations to identify suspects.
Genetic engineering is the deliberate alteration of the DNA of an
organism in order to change its character. This is already
practised in many areas, using DNA from one species to change
another. Genes from a fish that lives in very cold water, for
example, have been introduced into the DNA of a tomato, so that
the tomato can survive much colder temperatures. Tomato
growers will then be able to extend their growing season and
make more money. Genes from a jellyfish have been introduced
into pigs. The piglets resulting from this cross had bright yellow
snouts and trotters, glowing in the dark as jellyfish glow
underwater. The point of this exercise was to prove that modified
genes could be used to grow human organs, which could then be
used in transplant operations.

On June 26 2000, after ten years’ international cooperation

between scientists from Europe, Japan, Britain and America, the
first draft of the genetic sequence of a typical human being was
announced by Tony Blair, Prime Minister of Britain and Bill Clinton,
President of the USA. The sequence is called the human genome
and opens up endless possibilities. Genes that carry inherited
diseases, for example, may be isolated and removed from a
parent’s sperm or egg. In the future parents may be able to design
their own children. Scientists can now also compare human DNA
with the DNA of other creatures, providing them with vital
information about human lifespan and evolution. Some rather
surprising facts have emerged. For example, a pufferfish has the
same number of genes as a human. But more seriously, gene
science raises many moral and ethical issues that the world
community will now have to deal with, for example, is it right to
interfere with nature?

The story of Crick and Watson is one of the most famous and

fascinating scientific stories of the twentieth century, made
popular by Watson’s book. It has been published around the
world and dramatised for television. The reader may not
understand the science behind the pairing of nucleotide bases
that finally led Crick and Watson to win the race, but can still enjoy
the suspense of the race itself, recounted with much pleasure by
Watson.

In The Double Helix, Watson paints a very negative picture of

fellow scientist, Rosalind Franklin. This is mentioned in the
introduction. Franklin was a woman alone in a man’s world. She
was excluded from the bars and clubs that the other scientists
relaxed in after work, and therefore from the relaxed discussion of
ideas that so often leads to breakthroughs. She was very
protective of her research results, unwilling to share them with
patronising male colleagues, like Crick and Watson. Perhaps if
she and Crick had established a good working relationship, they
would have solved the problem of DNA much earlier. And if she
had not died of cancer in 1958, she would probably have been
awarded the Nobel Prize along with Watson, Crick and Wilkins, as
her work was so crucial to their achievement. In their
Nobel lectures, Crick and Watson did not even acknowledge
her contribution to their success.

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A B O U T T H E A U T H O R

THE DOUBLE HELIX

J

T e a c h e r’s n o t e s

by James D. Watson

© Pearson Education 2001

B A C K G R O U N D A N D T H E M E S

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The following teacher-led activities cover the same sections of
text as the exercises at the back of the Reader, and supplement
those exercises. Further supplementary exercises, covering
shorter sections of the book, can be found on the photocopiable
Student’s Activities pages of this Factsheet. These are primarily
for use with class readers, but with the exception of
pair/groupwork questions, can also be used by students working
alone in a self-access centre.

ACTIVITIES BEFORE READING THE BOOK

1 Find out how much students know about the discovery

of DNA. If appropriate, divide the class into two groups
– those who know a lot about it, and those who know
very little. Students share what they know in their
groups, perhaps discussing any relevant scientific
background they have. Finish with a whole class
discussion.

2 If your class knows a lot about the topic, ask them to

look at the Contents list. Organize students into pairs
or threes and give each group one or two chapter
titles. They predict together what the chapter will be
about. Afterwards students share their predictions with
the whole class.

3 What is DNA and why is it important? Can the class

arrive at a definition of DNA that they all agree with?
Write the final version on the board. Discuss current
and future uses. List them on the board.

ACTIVITIES AFTER READING A SECTION

Chapters 1–5

Students work in pairs. Each pair chooses three of the
characters from the first part of the book. They write one
or two sentences about each character, without
mentioning his/her name. They swap sentences with
another pair and work out who the other pair has chosen.
Alternatively, pairs read out their sentences for the whole
class to guess.

Chapters 6–10

Students work in groups of four. All four work at a
scientific foundation. Two students pretend they have
discovered something new about genes, such as how a
human baby chooses which genes from which parent.
Alternatively, it could be an application of science, for
example, an engine that runs on olive oil. The other two
students are in charge of the foundation’s money, which
they don’t want to waste. The first pair have to persuade
the second pair to give them enough money to research
their idea and make it work.

Chapters 11–15

Students work in pairs or small groups. Each group works
out a short description of the double helix for a non-
scientist. Each group then presents their description to the
class. They can use the diagrams in the book to illustrate
what they are saying. The class can then agree a best
description, taking sections from different groups’ work.

Alternatively, groups choose a different scientific process
or technological idea. They prepare a description of it and
present it to the class.

ACTIVITIES AFTER READING THE BOOK

Debate. Write this statement on the board: ‘Genetic
engineering is a good thing for the future of the world.’
Take a class vote. Divide the class in two. One half
prepares arguments in favour, the other against. There are
some ideas in the Background and Themes section above.
Students present their arguments and ask each other
questions. Take a second class vote. Has anyone changed
their mind?

It will be useful for your students to know the following new words.
They are practised in the ‘Before Your Read’ sections of exercises
at the back of the book.

Chapters 1–5

alpha (n) The first one, the beginnning. Or, in science - the first position
from a designated carbon atom in an organic molecule at which an atom
or radical may be substituted
bacteria (n) very small living things, some of which cause disease
bio- (suffix) relating to life, or living things
board (n) the group of people in an organization who make the rules and
important decisions
bond (n) a shared feeling or interest that unites people/a force of
attraction
carbon (n) a chemical element found in coal, diamonds and petrol
chromosome (n) a part of every living cell which controls the character,
shape etc that a plant, animal or person has
crystal (n) a solid mass of atoms/molecules with a regular form and flat
surface
deoxyribonucleic (n) DNA – a substance that carries genetic information
in a cell
gene (n) a part of a cell of a living thing which controls what it will be like
and how it will develop
helix (n) a spiral form or structure
hydrogen (n) a gas that is lighter than air, and that becomes water when
it combines with oxygen
ion (n) An atom or a group of atoms that has acquired a net electric
charge by gaining or losing one or more electrons
molecule (n) one or more connected atoms of a substance, which is the
smallest amount of it that can exist
neutral (adj) of, or relating to a particle, an object or a system that has
neither positive or negative electric charge
nucleic acid (n) any of a group of complex compounds found in all living
cells and viruses, composed of purines, pyramidines, carbohydrates, and
phosphoric acid. Nucleic acids in the form of DNA and RNA control
cellular function and heredity
nucleotides (n) any of various compounds consisting of a nucleoside
combined with a phosphate group and forming the basic constituent of
PhD (n) an advanced university degree
phosphate (n) a salt of phosphoric acid
protein (n) any of a group of complex organic macromolecules that
contain carbon, hydrogen, oxygen, nitrogen, and usually sulfur and are
composed of chains of amino acids. Protein is essential in the diet of
animals and people for the growth and repair of tissue
purine (n) a type of nucleotide base, shaped like two linked circles with
branches
pyrimidine (n) a type of nucleotide base, shaped like a circle with
branches
structure (n) the way in which the parts of something are organized and
are related to each other
virus (n) a very small living thing that causes diseases, or an illness
caused by this
X-ray diffraction (n) the scattering of x-rays by crystal atoms, producing
a diffraction pattern that yields information about the structure of the
crystal

Chapters 6–10

coil (n) something wound in a continuous series of loops; “a coil of rope”
phosphorus (n) a non-metallic element occurring naturally in various
phosphate rocks and existing in allotropic forms, especially as a
poisonous whitish waxy substance burning slowly at ordinary
temperatures and so appearing luminous in the dark, and a reddish form
used in matches, fertilizers etc
ribonucleic acid (n) a nucleic acid yielding ribose on hydrolysis, present
in living cells
TMV (n) the widely studied plant virus that causes tobacco mosaic; it was
the first virus discovered (Tobacco Mosaic Virus)

THE DOUBLE HELIX

T e a c h e r’s n o t e s

P u b l i s h e d a n d d i s t r i b u t e d b y P e a r s o n E d u c a t i o n

F a c t s h e e t w r i t t e n b y J a n e R o l l a s o n

F a c t s h e e t s e r i e s d e v e l o p e d b y L o u i s e J a m e s

© Pearson Education 2001

C o m m u n i c a t i v e a c t i v i t i e s

G l o s s a r y

P e n g u i n R e a d e r s F a c t s h e e t s

1 Read the introduction on page iv. It sounds as if there

will be a problem between two personalities in this
story. Which two?

(a) Crick and Watson

(b) Watson and Bragg

(c) Crick and Bragg

2 The introduction makes a kind of apology for a feature

of Watson’s book. What feature?

CHAPTERS 1–5

Chapter 1

1 Answer these questions.

(a) In what area of research did Sir Lawrence Bragg

make his scientific name?

(b) What did Bragg particularly dislike about James

Crick?

(c) Erwin Schrödinger’s book said that knowing one

thing was the key to understanding what life is.
Knowing what?

(d) What technique did Rosalind Franklin use to study

the molecular structure of crystals?

( e ) What does Watson discuss about Franklin that he

never mentions about his male colleagues?

2 Francis Crick was not an ordinary Cambridge scientist.

In what ways was he unusual? Talk to another student.

Chapter 2

1 Where ...

(a) did Watson blow up some petrol in a university

laboratory?

(b) was Herman Kalckar based?

(c) did Maurice Wilkins show the scientific world his X-

ray diffraction picture of DNA?

(d) did Watson first meet Wilkins?

(e) did Linus Pauling uncover his model of the alpha

helix?

2 This chapter describes Watson’s early years as a

scientist. He seems to have been bored by many
areas of science. Make a list of four things he was not
interested in or good at (pages 7–11). Compare your
list with another student’s. Would you expect a Nobel
Prize winner to have an early career like this?
Why/Why not?

Chapter 3

1 Answer these questions.

(a) Why did Washington at first refuse to allow Watson

to transfer to Cambridge?

(b) Why was Watson pleased when his landlady threw

him out?

(c) Crick and Watson discovered that they shared a

belief when they first met. What was it?

(d) Where did Crick and Watson decide that the key to

the uniqueness of each gene lay?

2 Choose some scientific words from this chapter. Write

definitions for them, using examples from the book.
Exchange definitions (without the words) with another
student. Can you find each other’s words?

Chapter 4

1 Put these events from Crick’s life in order.

(a) He studied pure biology at Cambridge.

(b) He registered for a Ph.D at Caius College.

(c) Bragg agreed that he and Crick had had the same

idea independently.

(d) Bragg threatened to kick him out of the Cavendish

after he finished his Ph.D.

( e ) Bragg and Perutz used one of Crick’s ideas in an

article but didn’t mention Crick’s name.

2 Odile and James Watson were both foreigners in

Cambridge. Imagine a conversation between them
about the English and the Cambridge way of life.

Chapter 5

Answer these questions.

(a) What detail about the composition of DNA had

Franklin discovered that Wilkins hadn’t?

(b) What project had Wilkins worked on before he

became interested in DNA?

(c) Why was Crick angry with Watson after Rosy’s talk?

(d) Why did Watson go to Rosy’s talk rather than Crick?

(e) Why did they think that sugar-phosphate backbone

had to be in the centre of the DNA molecule?

CHAPTERS 6–10

Chapter 6

Put these words in the correct sentences.

chains helical salt sugar-phosphate backbone water

(a) The King’s group had not found out which ... was

present in the DNA molecule.

(b) Crick and Watson’s first model had three ... twisted in

a helical shape.

(c) Franklin did not believe at this stage that the DNA

molecule was ....

(d) The amount of ... that Franklin had measured in DNA

was ten times the amount that Watson remembered.

(e) Crick and Watson began to question whether the ...

should be in the centre of the helix.

Chapter 7

Answer the questions.

(a) How many Mitchinson children are mentioned?

(b) Which of these activities did Watson enjoy?

(i) shooting pigeons

(ii) playing word games

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The Double Helix

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THE DOUBLE HELIX

Photocopiable

Students can do these exercises alone or with one or
more other students. Pair/group activies are marked.

Activities before reading the book

S t u d e n t ’ s a c t i v i t i e s

Activities while reading the book

© Pearson Education 2001

P e n g u i n R e a d e r s F a c t s h e e t s

(iii) lying on the floor in front of the fire

(iv) playing table tennis in the library

(c) What did Watson hope would prevent him leaving

Scotland?

(d) How much money would Watson have got from

Washington if he had stayed in Copenhagen?

(e) What type of nucleic acid does the tobacco virus

contain?

(f) Who funded Schramm’s research into TMV viruses?

Chapter 8

1 Put appropriate negatives in the gaps.

(a) Almost ... was interested in Hershey’s ideas on

bacterial viruses and DNA.

(b) If Lwoff had ... been present, the meeting would

have been a complete failure.

(c) The King’s group had spent ... time using Crick and

Watson’s molecular models.

(d) Watson decided that ... useful would come out of

his TMV work.

2 Read abour Chargaff’s research results on page 54.

This data will be vital in the discovery of the structure
of DNA. Why do you think this might be? Talk to
another student and compare ideas.

Chapter 9

Find the second half of each sentence.

(a) Delbrück couldn’t understand why

(b) Crowds of admirers

(c) Watson didn’t want to turn up to the garden party

(d) The party hostess was disappointed that

(i) came to see Linus Pauling talk about the alpha helix.

(ii) in shorts and walking boots.

(iii) Watson didn’t turn up in shorts and walking boots.

(iv) Watson loved Cambridge so much.

Chapter 10

Answer the questions.

(a) What new discovery about bacteria excited Watson

but failed to interest Crick?

(b) Francis Crick sent an article to Nature magazine. What

was it about?

(c) What idea about the DNA molecule did Franklin find

evidence for in her continuing research with X-ray
diffraction?

(d) What did Watson blame his stomach pains on?

(e) How did Crick and Watson learn in December that

Linus Pauling had discovered the structure of DNA?

CHAPTERS 11–15

Chapter 11

1 Answer these questions.

(a) What information did Linus not have that Crick and

Watson had?

(b) What mistake did Watson identify immediately in

Pauling’s paper?

(c) What vital information did Maurice give Watson on

his visit to London?

(d) On his way back to Cambridge, what did Watson

plan to do next?

(e) Why do you think he had to climb over the back

gate of the college?

2 Look at the exchange between Franklin and Watson

on page 72. Work with another student. One of you is
Franklin, the other is Watson. Turn the description of
their encounter into an actual dialogue.

Chapter 12

1 Why do you think all the scientists suddenly begin to

work together and support each other’s ideas?

2 Which of these statements does Watson believe by

the end of this chapter?

(a) All the bases formed hydrogen bonds to other

bases.

(b) Each molecule consisted of two chains with bases

in exactly the same order.

(c) The backbone would be completely regular.

(d) Each base was paired with another base of the

same type.

Chapter 13

Put these events in the order they happened.

(a) Crick observed that Watson’s structure did not fit the

Chargaff rules.

(b) He had found the double helix.

(c) He suddenly found a regular arrangement that made

sense with hydrogen bonding requirements and fitted
Chargaff’s rules.

(d) Jerry told Watson that he had used wrongly shaped

bases. The correctly shaped bases would not fit into
his structure.

(e) Within one hour of writing to Cal Tech to say that he

had discovered the structure of DNA, Watson found
that he hadn’t.

Chapter 14

Who might have said these things?

(a) ‘We must make a proper structural model straight

away.’

(b) ‘Congratulations, James. Imagine! A brother with a

Nobel Prize.’

(c) ‘The implications of this for gene copying are

amazing.’

(d) ‘Our X-ray data matches your double helix model.’

(e) ‘This data proves that the sugar-phosphate backbone

is on the outside of the molecule.’

Chapter 15

Look at the final sentence on Watson’s book on page
102. What do you think he means? Talk to another
student.

1 Write a personal response to The Double Helix. What

did you enjoy/dislike about it? How do you respond to
Watson’s attitudes?

2 Research some biographical information about

Rosalind Franklin in your local library or on the
internet. Organise your information so that you can
present it to the class. Compare what you have found
out with the picture James Watson paints in The
Double Helix.

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P u b l i s h e d a n d d i s t r i b u t e d b y P e a r s o n E d u c a t i o n

F a c t s h e e t w r i t t e n b y J a n e R o l l a s o n

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THE DOUBLE HELIX

Activities after reading the book