Genes, inheritance and variation guidance

2B1 You and your genes

Guidance AB1.1.1 Inheritance traffic lights

Teaching notes
This activity is designed to review KS3 inheritance Requirements (per student)
concepts and provide information on students’ • Activity sheet AB1.1.1 (optional)
starting points for this module. • small pieces of card (x3) per student (either
Give each student their cards. red, yellow, green or ×, , ?)
• Red or × means FALSE.
• Green or means TRUE.
• Yellow or ? means I’M NOT SURE.
The game follows this sequence:
a Read the question.
b Allow a short period of time for students to
consider their answer.
c Count ‘1, 2, 3, show your cards!’
d Students all hold up one of their cards at the
same time.
The questions are available on Activity sheet
AB1.1.1 if you wish to use them in a different type of
activity.

Answers to questions
1 Sexual reproduction needs a male and a
female. T
2 Only animals use sexual reproduction. F
3 Characteristics are passed on from parents to
offspring in sexual reproduction. T
4 In humans the male sex cells are called sperm
and the female sex cells are called ova (or egg
cells). T
5 In some people there is an extra type of sex cell
that produces identical twins. F
6 In humans the sperm cell has a tail so it can
move towards the ovum (egg cell). T
7 Fertilisation happens when a male sex cell and a
female sex cell join together. T
8 The instructions to make a new person are in a
fertilised egg cell nucleus. T
9 These instructions are called genes. T
10 All of a person’s characteristics are controlled by
their genes. F
11 Your blood group depends on what country you
grow up in. F
12 If you dye your hair red for more than two years,
it will make you have red-haired children. F

© University of York (UYSEG) and This page may be copied solely for use
the Nuffield Foundation B1.1- 2 in the purchaser’s school or college

B1 You and your genes

Guidance AB1.1.3 Variation

Teaching notes
This activity reinforces students’ understanding of Requirements
causes of variation. • OHT sheets of graph axes (for teacher)
Procedure • Activity sheet AB1.1.3 (optional-students)

Ask the students to identify whether their earlobes
are dangly or attached. d Height is also affected by your environment.
Record the data as a block graph on the blank OHT e So people are not just either short or tall.
axes.
f People’s height varies much more than their
Emphasise lack of ‘inbetweens’. earlobe shape.
Ask students to suggest other characteristics that
follow this pattern (eg blood group). Many of the
ones students tend to suggest are not single-gene
characteristics (eg eye colour is determined by
several genes). Most characteristics are determined
by several genes, and are affected by the
environment.
Superimpose provided graph of height data. This
graph shows height distribution for a population of
UK students aged 14–16.
Ask students to suggest why the distribution looks
different, not simply ‘tall’ or ‘short’:
• Height is determined by several genes – like most
of our characteristics.
• Height is also affected by environment – like many
of our characteristics.
You may wish some students to complete the activity
sheet as a record of the key ideas. There are
Textbook questions as an alternative.

Further information
If you have access to an interactive whiteboard you
may prefer to prepare graph axes on this, rather than
use OHT sheets.

1 Class data.
2 a Graph shape showing two possible earlobe
shapes.
b Graph shape showing continuous data for
height.
3 a Person’s earlobe shape is affected by just
one gene.
b So you have either attached or dangly
earlobes.
c Your height is affected by many genes.

the Nuffield Foundation B1.1-3 in the purchaser’s school or college


Guidance AB1.2.1 Cloning plants

Cloning cauliflower
Requirements (per group)
Procedure • Activity sheet AB1.2.1 (sheets 1 and 2)
1 The working area should be swabbed with 70% • 100 cm3 sterile distilled water
ethanol prior to the experiment.
• 100 cm3 20% Domestos solution
2 Once the cauliflower pieces have been sterilised
• test tubes containing 2–3 cm3 plant tissue
in bleach, quick, aseptic technique is needed to
growth medium (x3)
prevent contamination.
• sterile Petri dish
3 To flame metal instruments, dip them in alcohol,
• metal forceps and scalpel (count out/back)
pass briefly through a flame to ignite the ethanol.
As the ethanol burns off, it heats the surface of • non-absorbent cotton wool
the instruments to 70°C, killing any • aluminium foil
contaminating organisms. Do not heat forceps • labelling pen
and scalpels until red hot. • ethanol (for forceps/swabbing) (HIGHLY
4 The cauliflower pieces can be left in the final FLAMMABLE)
beaker of sterile distilled water (covered with a
Petri dish lid) until required. Technical notes
5 Before placing the cauliflower into each test tube, To make 775 ml of plant growth medium:
remove the cotton wool plug, then briefly flame the • 20 g granulated sugar
tube neck. Use flamed, cooled forceps to drop a
• 10 g agar
piece of cauliflower into the tube. Return the
• 4.7 g Murashige and Skoog (M&S) medium
forceps to the ethanol beaker. Flame the neck of
the tube before replacing the cotton wool plug. • 25 cm3 kinetin stock solution
6 The tubes should be kept in a warm, light place. The kinetin stock solution contains 0.1 g kinetin
Growth should be visible within 10 days. in 1 litre of distilled water. Kinetin does not
readily dissolve in water; adding one or two
7 If contamination has occurred it will also be
pellets of sodium hydroxide helps the dissolution
visible by this time. Failure of any growth usually
process. Stock solution should be stored at 4°C.
indicates that the bleach solution has not been
rinsed sufficiently from the plant tissue. Dissolve the sugar, M&S medium, and agar in
725 cm3 of distilled water. Mix in the stock
Further information kinetin solution, then dispense into test tubes
(2–3 cm3 per tube). Plug the tubes with non-
The procedure for cloning cauliflower is adapted absorbent cotton wool and cover the tops with
from Practical Biotechnology, National Centre for aluminium foil. Autoclave at 121°C for 15
Biotechnology Education (NCBE), 1995. Further minutes in a pressure cooker. When cool, the
information and protocols for a wide range of school tubes may be refrigerated until they are needed.
biotechnology practical work can be found on the
M&S medium and kinetin are available from
NCBE website; see WEBLINKS.
school science suppliers, e.g. Philip Harris Limited.



Guidance AB1.2.1 Cloning plants

11 To kill any microorganisms on the surface of the
Health and safety notes
cauliflower. Contamination of the growth medium Ethanol should be kept away from exposed
could prevent the new plant from growing flames. You may wish to pre-prepare flamed
properly. forceps and scalpels for students in some
classes. Alternatively, they can be pre-sterilised
12 To reduce water loss from the test tube.
in an autoclave.
13 Every plant cell contains all the genetic
Plastic gloves should be worn when handling
information needed to make a new plant. When
kinetin – the solution used by the students
the plant is growing, some of the plant cells stay
present no problem.
unspecialised. They can develop into any type of
plant cell. Students should wear eye protection. Students
need to take especial care when using scalpels.



Guidance AB1.2.2 Twin studies

Teaching notes
As students work through this activity they practise Requirements (per student)
converting data from a table to bar charts. The bar • Activity sheet AB1.2.2
charts will then make it easier for them to draw • graph paper
conclusions from the information they are given.
The data comes from an early (1937) but important
US study on twins, which showed how different To find out
genetic characteristics appear to be affected to a This provides extension for some students. Direct
greater or lesser degree by environmental students to the weblinks provided for this lesson. Ask
influences. Subsequent studies have confirmed the them to find out more about twin studies. Look for
concept although there is still considerable variation evidence that students have extracted scientific
in results. If anything, the consensus of data is that understanding from the twin stories, and that they
genes have a stronger influence than was originally recognise the type of data that would need to be
thought, and environment less. collected to have validity, etc: see WEBLINKS
Students need to grasp the idea that, the smaller the
differences between them, the more alike the pair
are and so the stronger the genetic influence.
This data suggests that height is surprisingly strongly
genetic, mass much less so and IQ clearly
influenced by both genes and environment.

Answers
1 Suitable bar charts
2 Characteristic mainly decided by genes –
environment has little effect, so little difference
between identical twins reared apart or together.
The bigger the influence of the environment, the
bigger the difference between identical twins
reared apart and identical twins reared together.
3 Height – different environment has relatively
small impact on final height of identical twins.
4 They have identical genes but have been reared
in different environments, so can see the effect
of environment on different characteristics. This
allows scientists to discover how much genes
and the environment influence different
characteristics.
5 They are affected by the environment more or
less equally.
6 Any valid points, eg how many pairs of twins
were studied, the age at which they were
measured, if the data was all collected by the
same people in the same place using the same
instruments, etc.



Guidance AB1.3.1 Inheriting genes

Teaching notes
The animation (IB1.3.6) is designed for students to Requirements (per student or group)
work through themselves. • Activity sheets AB1.3.1
If you have access to an interactive whiteboard, you • Animation IB1.3.6
may prefer to use a whole-class teaching approach.
If you do not have access to the animation, students
could complete the activity sheet using the Textbook.

Fertilisation
1 Humans have 23 pairs of chromosomes.
2 The bands on the chromosomes show different
genes.
3 Chromosomes are in pairs, so genes come in
pairs too.
4 The only cells that don’t have pairs of
chromosomes are the sex/gamete cells.
Why don’t brothers and sisters look the
same?
5 Sperm cells get a copy of just one of the
chromosomes from each pair a man has.
6 It is very unlikely that two sex cells get the same
combination/mix of chromosomes.
7



Guidance AB1.4.1 Male or female?

Teaching notes
The activity illustrates the random nature of Requirements (per student)
fertilisation. Check that students know the sex • Activity sheet AB1.4.1
chromosomes of a human male and female before
starting the game. Students select randomly an Requirements (per group)
‘ovum’ and ‘sperm’ card from each bag. The cards • small bag with 20 circles of card, each
should be replaced in the bags and mixed well after marked with an X (‘ova’ bag)
each ‘fertilisation’.
• small bag with 20 sperm-cell shaped cards,
half marked X and half Y (‘sperm’ bag)
1 X or Y Technical notes
2 All X It is helpful for clearing away if the ova and
3 Sperm cell sperm cards are different colours.
4 Students usually consider that Henry VIII was
incorrect in blaming his wives for his lack of male
heirs.

Further information
Students may be aware of anecdotal stories of
families which appear to produce a greater
proportion of male or female children. The small
sample sizes within a family do not make this data
significant. The 2001 UK census lists 28 581 233
males and 30 207 961 females. There have been
individual research reports that suggest sperm
carrying a Y chromosome are more susceptible to
toxins, such as those in cigarette smoke, than X-
carrying sperm.



Guidance AB1.4.2 Inheriting sex

Teaching notes
The animation is designed for students to work Requirements
through themselves. • Activity sheet AB1.4.2 (per student)
If you have access to a data projector or an • Animation IB1.4.4 Sex
interactive whiteboard, you may prefer to use a
whole-class teaching approach.
4 A man’s sex chromosomes are XY.
If you do not have access to the animation students
could complete the activity sheet using the Textbook. 5 A human sex cell has 23 single chromosomes.
6 Row 1: XX XX
Answers to questions Row 2: XY XY
1 A human body cell has 23 pairs of Chance of child being male: 50%; ½
chromosomes.
2 Pair 23 control a person’s sex.
3 A woman’s sex chromosomes are XX.



Guidance AB1.4.3 Caster Semenya’s story

Teaching notes
This activity provides students with an opportunity to Requirements (per student)
explore a contemporary story of an athlete where • Activity sheet AB1.4.3
sex testing and gender issues meet. Caster • Internet
Semenya is a young South African who has been • use WEBLINK to get students started
brought up and schooled and has competed as a
girl. However, once she appeared on both the
national and international stage, questions were
raised as to her biological sex as a result of both her
appearance and her performances.
In July 2010, a year after winning the gold medal, the
International Association of Athletic Federations
(IAAF) announced that its panel of medical experts
concluded she could compete again.
Students are asked to investigate the story and
produce a presentation or article summarising the
main facts and the problems that have arisen. It
provides another opportunity to discuss the sex/
gender issues and also to consider how and why it
might have proved so difficult to determine whether
Caster is male or female. Use the WEBLINK
available.



Guidance AB1.4.4 Looking at sets of chromosomes

Teaching notes
This is an extension activity. Requirements (per student or group)
• Activity sheets AB1.4.4
1 Pair 23 in a male body cell is XY; in a female
body cell it is XX.
2 The Klinefelter’s karyotype has three sex
chromosomes instead of a pair – XXY.
3 A person with Klinefelter’s is male because they
have a Y chromosome with the gene for male
sex hormone. So the embryo develops into a
male.
4 The instructions for how an organism develops
are found in the form of genes found on
chromosomes. Genes describe how to make
proteins which might be structural or functional.
If there are sections of genes missing or
duplicated the proteins may not form or form
incorrectly, affecting their function and causing
the serious symptoms.



Guidance AB1.5.1 Alleles

Teaching notes
The animation (IB1.5.4) is designed for students to Requirements (per student or group)
work through themselves. • Activity sheets AB1.5.1

1 People have two copies of every gene because
they inherit one copy from each parent.
2 Different versions of a gene are called alleles.
3

4 John has one allele for attached and one for
unattached earlobes. The unattached allele is
dominant. (You only need to have one dominant
allele for a feature for it to show up.)
5 Carl has two alleles for attached earlobes.
(There is no dominant unattached allele, so he
has the recessive feature.)



Guidance AB1.5.2 Modelling fertilisation

Teaching notes
These activities are designed to clarify the distinction
Requirements (per group)
between gene and allele, and to illustrate that • Activity sheets AB1.5.2 (sheet 1
fertilisation and the transfer of alleles from a pair into Foundation/sheet 2 Higher)
sex cells are both random processes. Before • beads (e.g. plastic poppet beads) in two
starting, clarify with students what is meant by a contrasting colours (200 of each colour)
‘scientific model’, i.e. to a scientist a model is a • beakers for the beads (× 3)
simplified way of explaining how something is • marker pen or chalk
arranged or how it functions. In this activity students • OHT of following guidance (for teacher)
model the way information is passed on from parents
to their offspring using beads. Using these models
they test the ideas used to explain in theory how
Health and safety notes
different characteristics are inherited – and see if It is probably worth mentioning not to put beads
those ideas work. in mouth, ears, etc!

To show that fertilisation
happens by chance (sheet 1) Using beads to show how
a In this investigation the beads represent sex different alleles can be
cells – the egg and sperm cells. Use red beads
to be sperm, and yellow beads to be egg cells. inherited (sheet 2)
Put all the 200 sperm beads in a ‘male’ a Students will make 100 new plants. Ask them to
container, and all the egg cell beads in a ‘female’ predict the number of tall and short plants
container. Mark 20 of the sperm beads and 20 of expected.
the egg cell beads with a black spot. Put them b Put 100 red and 100 yellow bead ‘alleles’ in the
back in their containers and mix them in with the ‘male’ container and mix them up well. Do the
unmarked beads. same for the ‘female’ container to show the
b Pull out one sperm and one egg bead without alleles in the female sex cell.
looking. These two beads represent the fertilised c Take one bead from each container to
egg cell. Record if either bead carries a black determine the alleles in the new plant. Students
spot on the tally chart. use a tally chart to record the pair – 2 red, 1 red
c Students will make 50 fertilised eggs. Ask them and 1 yellow, or 2 yellow.
to predict how many pairs of beads will have: d Replace the beads in the container they came
• a black spot on just one bead from each time.
• black spots on both beads Answers to questions
• no black spots at all 1 & 2 These will depend on the predictions made.
3 How well they were mixed. Whether students
Answers to questions looked in the beaker when they picked.
1 This depends on the predictions made. These simulation exercises work well, but it is
2 In the experiment it was chance which bead you important to make sure that students are clear about
picked up each time. what the beads and beakers are representing in
Fertilisation is like that too. each case. It is particularly important that the
You cannot predict which sperm will fertilise an concepts of genes and alleles are explained
egg cell. carefully, as students often get these confused.
Students need to make a fairly large number of fertilised
ova for the statistics to work. This does not add much to
the time required for the activity. Alternatively, collect
group results into whole-class data.



Guidance AB1.5.2 Modelling fertilisation

Using beads to show how different alleles
can be inherited
Pea plants are either tall or short. Their height is controlled by just one gene
with two different possible alleles. The tall allele is dominant. The short
allele is recessive. (This is different from humans. Human height is affected
by many genes.)
In this investigation you are going to model the breeding between two tall
plants. Both these tall plants had one tall and one short parent. You will use
beads to represent the alleles for tall and short, e.g. red for tall, yellow for
short.



Guidance AB1.5.3 Genetic crosses

Teaching notes
The animation is designed for students to work Requirements (per student)
through themselves. • Activity sheet AB1.5.3

Genetic crosses



Guidance AB1.5.4 Pairing up

Teaching notes
This is a very quick, simple, activity to consolidate or Requirements (per class)
recap students’ knowledge of symbol representation • Activity sheets AB1.5.4 (one or more sheets
for dominant and recessive alleles. per student)
Depending on class size, give each student one or • OHT of animal outlines copies (x5)
more chromosome cards until all are distributed. • packs of OHT pens of various colours (x5)
The task is to find their matching chromosome pair,
and mark the OHT animal with the feature the alleles Technical notes
determine. A set of chromosome cards could be cut out
There are five animal outlines. Give one OHT sheet and laminated before the lesson.
to each of five students around the room. They are
the base for that animal.
When students find their matching pair, they
annotate the feature on the OHT sheet.
Use the completed OHT sheets as a basis for quick
check questions, eg what would this feature have
been if the animal had different allele pairs?



Guidance AB1.5.4 Pairing up



Guidance AB1.5.5 Predicting inheritance

Teaching notes
The activity sheets present questions to practise Requirements (per student)
genetic crosses. The later questions have less • Activity sheets AB1.5.5
student support. You will want to select questions
most appropriate to your students.
The final sheet has blank Punnett square diagrams 4
to support students if required on the more difficult
questions.

1 a

b Short plant must have alleles tt.

The percentage of tall plants is 50%.
2

3



Guidance AB1.6.1 Cystic fibrosis

Teaching notes
This activity is an alternative to note-making which Requirements (per student)
may be appropriate for some students. Students • Activity sheet AB1.6.1
identify symptoms and treatments for cystic fibrosis. • Animation IB1.6.7 (optional)
The second sheet has instructions which you may
prefer to photocopy, or alternatively display on
OHT/whiteboard for students to follow.
The first part of Animation IB1.6.7 Reading the gene
shows the location of the lungs and pancreas, and
illustrates mucus build-up along lining tissue. It may
be useful to show this briefly to the class.



Guidance AB1.6.2 Two inherited conditions

Teaching notes
Students should conclude for themselves that cystic Requirements (per student)
fibrosis is determined by a recessive allele. • Activity sheets AB1.6.2

Answers to questions b The allele for cystic fibrosis is recessive.
1
A person with one copy of the allele will not
Name of Huntington’s Cystic have the disorder.
disorder disease fibrosis They are a carrier.
Key H = Huntington’s F = normal The allele for Huntington’s disease is
allele allele dominant.
h = normal allele f = cystic A person with one copy of the allele will
fibrosis allele have the disease.
So there are no carriers of Huntington’s
Does one of
disease.
the parents
of the
affected yes no
people also
have the
disease?

What are the
allele pairs
of people HH or Hh ff
with the
disorder?

What are the
allele pairs
of people hh Ff or FF
without the
disorder?

2 A recessive allele will only cause an effect when
there are two of them.
3 a Huntington’s disease: there are no carriers.
Cystic fibrosis: Rob, Jane, Paula and Keith
must be carriers for the cystic fibrosis allele.
Some students may understand that Leon
and Clare, and Owen, could be carriers. We
cannot be certain they are not from the
information in the family tree.



Guidance AB1.7.1 Shall we have the test?

Teaching notes
Students are given four different scenarios and
asked to plan the advice they would give to the Requirements (per group)
couples who are all concerned about having fetal • Activity sheets AB1.7.1
genetic testing for different reasons. Students can • OHT of possible viewpoint (or student copies)
work in small groups or individually.
• Internet access or printed web pages with
Help students to understand that the advice given background information on reliability of
will vary from couple to couple depending on their genetic testing (optional – also provided in
circumstances and the importance of the Textbook sections E & G)
information they are seeking. They also need to
suggest that couples consider whether they would
proceed to a termination if they found there was a
problem with the fetus. In one instance in particular,
where the parents are simply desperate to know the
sex of the unborn baby, the risks of the test
outweigh the benefits of the knowledge and they will
probably be able to find out a little later in the
pregnancy with an ultrasound scan and virtually no
risk.

Useful websites
The websites provided are for the Royal College of
Obstetrics and Gynaecology; and genetics in
general. They are very clear and informative about
chorionic villus sampling and amniocentesis: see
WEBLINKS



Guidance AB1.7.3 Decision making

Teaching notes
In this sequence of activities students develop a role- Requirements (per group)
play to explore the ethical issues surrounding pre- • Activity sheet AB1.7.2
natal testing for a genetic disease. • Activity sheet AB1.7.3
There are three roles within each group: a couple • OHT of possible viewpoint (or student copies)
and their genetic counsellor. When grouping • Internet access or printed web pages with
students, keep in mind that the role of genetic background information on reliability of
counsellor will need a reasonable grasp of the genetic testing (optional – also provided in
science ideas. Textbook sections F & G)
The first activity is a small-group discussion of the
options available to the couple. A summary (in the
form of a flowchart) of the available options for the viewpoints that they may not be in agreement with.
couple is provided at the end of these notes to copy Possible viewpoint statements which you could use
onto OHT or give to students. As this is the first with students are listed at the end.
occasion during the module that students focus in Students should then be given a set time period to
depth on the Ideas about Science explored in this prepare and present their role-play.
module, they are likely to need help in structuring
their discussion. This is provided by the table on Useful websites
sheet 2 of the activity. Alternatively, if you wish to The Guardian website has a special report on
give students less structured support, you could use genetics and ethics covering a wide range of issues:
AB1.7.2 Ethics. see WEBLINKS.
The table on sheet 2 can be completed by one
member of the group as a record of their research
and discussion. It focuses students on the key
information they need to consider before developing
their role-play. At the end of their discussion each
group should have ranked the options available to
the couple. Differences in opinion are likely, but a
group should try to reach agreement if they can. If
this is not possible, students should reflect this
controversy in their role-play.
When students hold strongly opposed viewpoints it
can be useful to step in and bypass the rank
ordering. Sensitivity to this possibility is important
where, for example, any questioning of a firmly held
family position may be considered as an insult to
students’ family beliefs. Controversy involves values,
so it is reasonable to set the discussion in the
context of respect for each other, acting in the
interests of the group by listening to opposing views,
and prohibiting remarks which may be offensive to
other members of the class.
It is worth reminding students that they are going to
be expressing views in the context of a role-play, and
that therefore these views are not necessarily their
own. Perhaps suggest to different groups that the
two people within each couple are in broad
agreement, or that they disagree. In this way
students are directed to consider and present



Guidance AB1.8.1 Finding the right medicine

Teaching notes
Students are given a piece of extra reading about Requirements (per student)
pharmacogenomics and then asked to answer a • Activity sheet AB1.8.1
series of questions. Questions are provided at F and • Internet
H levels.

Answers F 5 Any two sensible ideas, for example:

1 All of the human genes • It allows doctors to use the minimum effective
dose of drug for each patient, which minimises
2 The science of developing new medicines using
risk of side effects and saves NHS money by
knowledge about drugs/pharmaceutical
reducing drug bill.
expertise and information on the human
• It means doctors only prescribe drugs which
genome/individual genetic makeup.
are effective for a particular patient – benefits
3 Certain painkillers/ kappa opioids work better for patient as always given effective drug and
females than males. OR Many over-the-counter saves NHS money by avoiding trying drugs
painkillers work best in pale-skinned, red-haired which don’t work for patient.
women.
• It avoids adverse drug reactions. This benefits
4 Only giving drugs to which you will not have a patients – they don’t risk death or hospital
bad reaction. Calculating the lowest effective admission – and saves NHS money treating
dose. the result of adverse drug reactions.
5 Costs lots of money to develop personalised 6 It costs lots of money to develop personalised
medicines – to sequence the genome and find medicines – to sequence the genome and find
the right medicines. Drug companies might not the right medicines. Drug companies might not
do this for developing world countries which do this for developing-world countries which
might not be able to afford the individual testing might not be able to afford the individual testing
to use the specific drugs. Is it ethical if it is to use the specific drugs. Is it ethical if it is
possible to develop drugs but they don’t do it? possible to develop drugs but they don’t do it?
Any valid points which show student has thought Any valid points which show student has thought
about potential difficulties. about potential difficulties.
7 Any thoughtful point, eg in some cases one drug
Answers H will work for the majority of people. If only a
1 All of the human genes small group need an alternative, it won’t be
2 The science of developing new medicines using financially viable for drug companies to develop
knowledge about drugs/pharmaceutical an alternative drug. Should they be forced to do
expertise and information on the human so? Or should people with the minority genetic
genome/individual genetic makeup. sequence be left without effective treatment?
3 Certain painkillers/kappa opioids work better for
females than males. OR Many over-the-counter
painkillers work best in pale-skinned, red-haired
women.
4 If they know the genome sequence of normal
cells and cancer cells they can develop drugs
which target only the cells with the changed
genetic material of the cancer cells.



Guidance IB1.8.4 Genetic testing of adults

Teaching notes
Use Presentation IB1.8.4 Genetic testing of adults 1 Requirements (per student)
to introduce genetic testing of adults and the ethical • Presentation IB1.8.4
issues this raises. In this case testing adults before • Whiteboard and projector
they start a family has prevented any babies with
Tay Sachs disease being born in the US, Israel or
the UK.

Slide 1: Introduction
Slide 2: Image of crowd. Text reminds students that
everyone has faulty genes with dangerous alleles
but most of the time they don’t cause problems. Ask
students when these alleles do cause problems.
Answers should include: when the problem is a
dominant allele or when two people carrying the
same recessive faulty allele have a child.
Slide 3: Introduction to Tay Sachs disease to
support book content. As always with genetic
diseases, this needs sensitive handling. However, as
a result of the genetic screening described, it is
highly unlikely that any pupils will have had any
experience of this genetic condition in their families
in recent years. Point out that it is the lack of a single
enzyme that causes all the problems.
Slide 4: Rabbi Joseph Ekstein devised the screening
programme in response to losing four of his own
children to Tay Sachs. There is a screening test
which shows up carriers and this made the
programme possible.
Slide 5: Punnett square showing how two carriers
can pass on the lethal combination.
Slide 6: Since the 1980s, Jewish couples of
European descent have taken genetic tests and, as
far as possible, two carriers have not been matched.
You could explain to students that in more traditional
Jewish communities a matchmaker would arrange
couples and so this made it easier to avoid matching
two carriers. Carriers who marry use pre-natal fetal
testing and termination to prevent the birth of
affected children.
Slide 7: Highly successful – virtually no babies with
Tay Sachs have been born in the US, Israel or the
UK in recent years.



Guidance AB1.9.2 Stereotype of the karyotype

Teaching notes
This is an extension activity. Requirements (per student)
• Activity sheet AB1.9.2
1 Male sex cells usually have XY chromosomes.
2 Human body cells normally contain 46
chromosomes.
3 An XYY person has 47 chromosomes in each
body cell.
4 Three unusual phenotypes of XYY men are:
• minor out-turning of the elbows
• pectus chest deformity
• crooked left eye
5 The insurance company may think that he is
more likely to show violent behaviour, and thus
become injured. They may think that his chest
deformity or crooked eye may make him more
likely to need health treatment.
6 John’s bad behaviour could be due to his diet
rather than just being because he is XYY. The
fact that he is XYY does not mean that this is the
cause of his bad behaviour.
7 No, because:
• XYY men are tall so they are more noticeable
and may therefore be targeted more for fights,
or be more memorable to people – making
them more likely to be arrested.
• Most XYY men are not in prison, so all XYY
men are not criminals.
8 A stereotype is a ‘label’. The XYY stereotype
labels all XYY men as ‘likely to be violent
criminals’. XYY men are mostly decent, good
people, so the stereotype is unfair and unjust.
When we label people as ‘abnormal’ in some
way we may make assumptions about them
which are not true.



Guidance AB1.10.2 Embryo selection – what should be allowed?

Teaching notes
In this activity students take on the role of a Requirements (per group)
government regulatory body (currently, September • Activity sheets AB1.10.2
2010, the Human Fertilisation and Embryology • Activity sheet AB1.7.2
Authority: see WEBLINKS • access to Internet (optional – depending on
Teachers should visit the above website, to make time allocated to the activity)
sure that they know the current rulings as these
change. In summary, PGD is allowed for serious
single-gene disorders such as cystic fibrosis; to
select for an embryo which is a tissue match for a
Notes
seriously ill child; in sex-selection for medical Pre-implantation genetic diagnosis (PGD): this is
reasons but not for family balancing. a recent alternative treatment. It was first introduced
in 1990 for gender selection of embryos in cases of
Ensure that students are clear about the role of the
sex-linked inherited diseases. In 1992 PGD was first
regulatory body before beginning the activity. If time
successfully used in a case of cystic fibrosis. All
permits, more able students could be asked to
applications to use PGD must currently be approved
research this information themselves. The relevant
by the regulatory body.
websites may not be accessible for all students.
Alternatively, a summary card is provided in the Friedreich’s ataxia: particularly recommended is
activity sheets. ‘The Gift’, a video drama based around the issue of
embryo selection, from the Wellcome Trust
Students should work in groups of four. It does not
Education page. Set both in the present and 30
matter if there are extra students. Allocate each
years in the future, it explores the options available
student in the group a ‘Case’ card 1–4.
to three generations of a family affected by the rare
Rearrange the class so that all Case 1 students are genetic disorder, Friedreich's ataxia.
together and so on.
Human Fertilisation and Embryology Authority
Using AB1.7.2 Ethics as guidance, students consider (HEFA): the HFEA is one of the few statutory bodies
whether embryo selection should be allowed in their worldwide which regulates, licenses and collects
case. The activity sheets include a table for them to data on fertility treatments such as IVF and donor
record their views. insemination, as well as on human embryo research.
Students should have a set time limit to discuss their It was set up in 1991 to monitor and inspect all
case so that they can present it to their group. At the clinics in the UK offering fertility treatments or storing
end of this time they should be able to: eggs, sperm, or embryos.
• explain what the case is The HFEA consists of 21 members appointed by UK
• say what the expert group decision was Health Ministers. Members should not be selected as
• explain the reasons for the decision, with representatives of a particular organisation, but in
reference to the ethical framework on AB1.7.2. respect of their personal expertise. At least half of
the HFEA members come from disciplines other than
In their group of four, they are the ‘expert’ on their case.
medicine or human embryo research. They should
Running the activity in this way is therefore less
be appointed in line with the Nolan principles, seven
threatening for students than presenting their views to a
guidelines for individuals holding public office:
larger audience. This would be an alternative approach
www.ost.gov.uk/policy/advice/copsac/annex.htm.
where students are more confident.
The HFEA has carried out public consultations to
Some students will not agree with embryo selection
gather views on pre-implantation genetic diagnosis,
in any case. They should be encouraged to argue
and its use in gender selection. The consultation
their case within the bounds of this role-play, i.e.
documents are available on its website at time of
embryo selection is allowed subject to regulation.
press, and they are very useful sources of
As a member of the regulatory panel, they must
information about this technology.
develop arguments to win over their colleagues in
particular cases, thus restricting the use of embryo
selection as much as they are able to.



Guidance AB1.11.1 Asexual reproduction

Answers
1 Unicellular.
2 Asexual.
3 Clones.
4 The environment is also a source of variation.



Guidance AB1.11.2 Stem cells

Teaching notes
This activity introduces students to different Requirements (per student or pair)
viewpoints on embryo cloning, and recaps the • Activity sheet AB1.11.2
decision-making ethical framework introduced • Scissors and glue
through the Ideas about Science in this module. • Computer and printer access (optional – as
The first sheet of the activity presents a number of alternative to cut and stick)
viewpoints for/against cloning embryos to produce
stem cells for potential medical treatments.
b Opinion: This treatment could relieve
Students should separate the arguments into for and
diabetics from injecting synthetic insulin.
against piles then distinguish them by type:
However, this treatment is unlikely to be a
• decision made by weighing up consequences for
cure.
all involved
5 No, this account seems impartial.
• decision made because process is considered
fundamentally right or wrong. 6 Ethical arguments in relation to using embryos

The second page of the activity sheet introduces
students to some of the language they will meet
throughout GCSE Science when discussing or
developing arguments: opinion, speculation,
evidence, explanation, fact.
The first question introduces the terminology to the
class.
If you have copies of a recent news story, extend this
introduction by asking students to identify key
statements in the report.
The terminology is then put in the context of stem
cells and diabetes.

Answers
1 Opinion - Someone's viewpoint. May not be
based on evidence.
Speculation - Suggesting possibilities that might
happen. Goes beyond facts.
Evidence - Information that is linked to the issue.
Explanation - An idea to explain some evidence.
Fact - Something that people accept as being
proved true
3 a Description: transplants of stem cells from
their own bone marrow
b Evidence: Out of 23 patients, 20 no longer
required insulin injections. One patient
remained insulin-free for up to 4 years.
Speculation: This treatment could relieve
diabetics from injecting synthetic insulin
4 a Explanation:This is because the cells that
make insulin are all destroyed after that time.



Guidance AB1.12.1 Adult stem cells

Teaching notes
Students are given a sheet of comments giving them Requirements (per student)
information and opinions about adult stem cells. • Activity sheet AB1.12.1
They use these sheets along with the Textbook, if
needed to fill in the table provided. This could also
be done as a class exercise, filling in the table
together and using the process as a basis for
discussion about the ethical issues raised by both
processes.
There are many different valid and sensible points
which could be raised – a few possibilities are given
here.

Possible answers
Embryonic stem cells Adult stem cells
Large numbers can be Only found in tiny
produced numbers
Relatively easily grown Relatively difficult to
grow
Cells very flexible – can be Cells can be used to
used to produce very wide produce a more
range of tissues limited range of
tissues
Cells relatively undamaged Cells may have DNA
damage – mutations
– depending partly
on the age of the
adult
Tissues formed may be Tissues formed have
rejected – recipient needs same antigens as
immunosuppressant drugs original cells so no
rejection problems
Ethical issues for some No ethical issues as
people with using cells taken from
embryonic cells patient



Guidance AB1.12.2 The cloning debate

Teaching notes
There are four scenarios for students to work with. Requirements (per student)
Depending on the size and ability of the class, • Activity sheet AB1.12.2
students can work individually or in groups. They • Internet access
may manage only one of the activities during the
lesson or they may work through all four! Some of
the activities can be completed more successfully C Cloning endangered or extinct animals
with access to ICT; if it is not available students will 1 No living tissue to get DNA from; high-quality
be more limited in the scope of their answers. fossils rare; difficulties of getting DNA from
In most of these answers students are required to extinct animals; no animals of the same species
express opinions as well as report biological facts. to provide eggs or act as surrogate mothers;
Answers different habitat, food resources, etc. Any
sensible points.
A Cloning farm animals and animals for
2 Look for evidence that students understand both
medicines
the science and the concept of ethical
Students should show awareness of the benefits of
arguments, and that they present arguments
cloning of top-quality animals and embryo cloning in both for and against the processes.
farm animals, and the importance of adult cell
cloning in producing as many animals which give D Cloning humans
medicines in their milk as possible. Disadvantages
Look for evidence of a good understanding of the
include the small numbers of animals which result,
ideas both for and against the process, and an
the risks and problems of adult cell cloning, etc.
awareness of technical difficulties, biological
Students should show clear understanding of dilemmas and ethical problems
different ethical positions.

B Cloning pets
1 a Different environment – different mother,
different uterus, different time so different
foods, etc will be available. Environment
affects the phenotype as well as the genotype
so the animal is likely to have a different
character – and behave differently – it will
have different experiences, etc. Cats’ coats,
even with identical genes, can have a very
different pattern and colour, so the clone may
not look the same as the original. Any other
sensible points.
b Look for biological and ethical comments in
student’s answers to this question.
2 a The foal will be genetically identical to the
original champion horse but will be a stallion
and therefore able to act as a stud when it is
adult, so high-quality genes can be passed
on. It can make a lot of money for the
owners. Any other sensible points.
b Any sensible and thoughtful points.



Guidance IB1.12.8 To clone or not to clone?

Teaching notes
Students view the presentation and then complete Requirements (per student)
Activity AB1.12.2 The cloning debate. • Presentation IB1.12.8
• Activity AB1.12.2
Slide 1: To clone or not to clone?
Students are introduced to the idea that many
Slide 8: Cloning race horses?
species of animals have been cloned and that
cloning can be used in very different ways. They are This image shows a foal who is a clone of a highly
going to look at some of the decisions that need to successful endurance champion who is a gelding.
made about this fast-developing technology. Race horses are often gelded, though if they then
become extremely successful they cannot be used at
Emphasise, that in most of the examples described,
stud. But if the gelded horse is cloned, the foal will
it is adult cell cloning that is the basic technique.
be a stallion and can be used for breeding.
Slide 2: Dolly the sheep
Slide 9: Cloning endangered species
Image of Dolly the sheep with her own first lamb,
Scientists have tried to use cloning to increase the
Bonnie. This reminds students that adult cell cloning
numbers of some of the most endangered species of
is not easy. It took 277 eggs to produce 1 live lamb.
animals. There was great excitement when Noah the
Slide 3: Cloned cattle baby gaur (a very rare breed of wild cattle) was born.
Unfortunately, he died of infection within 2 days of birth.
Reminder that cattle are often cloned by embryo
Cloning mouflon (rare wild sheep) has been more
cloning (when a single embryo is split into lots of
successful. But very few endangered animals have
individual cells, which each develop into another
been cloned. One problem is that animals which are
embryo to be implanted in a surrogate mother cow).
closely related but not the same species usually have
The cows on the slide were produced by the less
to act as both egg donors and surrogate mothers.
common method of adult cell cloning.
Slide 10: Cloning extinct organisms
Slide 4: The first dog clone
This slide shows an almost perfect fossil of a baby
The first dog to be cloned was produced in South
mammoth found in the Siberian permafrost in 2007.
Korea in 2005. The photo shows Snuppy the clone
Scientists think that it may one day be possible to
as a puppy alongside the original dog. The scientist
clone extinct animals form DNA extracted from
who produced Snuppy was later disgraced because
extremely well-preserved fossils like this one. Again
he faked evidence in work on human stem cells.
one problem is that animals which are closely related
However, DNA testing proved that Snuppy really was
but not the same species would have to act as both
a clone.
egg donors and surrogate mothers. Also the
environment, food supply, habitat, etc of extinct
Slide 5: Cloning pets 1
animals no longer exists.
This slide shows CopyCat, the first cat to be cloned
successfully, and Little Nicky, the first pet cat to be Slide 11: Cloning primates
commercially cloned.
Cloning primates is proving much more difficult than
cloning most other mammalian species, although
Slide 6: Cloning pets 2
early embryos and embryonic stem cells were
This slide shows an American couple with the first produced in 2009.
commercially produced cloned pet dog – all
£100,000 worth of him! Slide 12: Human clones
The final slide simply raises the issue of human
Slide 7: Cloning horses
clones – not only whether it can be done (so far the
The first cloned horse, who was both daughter and answer is no although one or two maverick scientists
identical clone of the mare who gave birth to her. claim to have tried) but whether it should be done.



Guidance AB1.A.1 Huntington’s disease

Teaching notes
This activity introduces Huntington’s disease. It is Requirements (per student)
supported by Section C in the Textbook. • Activity sheet AB1.A.1

1 Both men and women can suffer from
Huntington’s disease.
Only one parent needs to have the condition for
it to be passed on to their children.
2 a Huntington’s disease is an inherited
condition. Eileen thinks that David is more
likely to have inherited the condition because
he looks a lot like his dad.
b Sarah is just as likely as David to have
inherited the condition from their dad. It has
nothing to do with what other features they
may have inherited.
c No – it’s a bit late. Symptoms of Huntington’s
disease are usually noticed between ages 35
and 50 years.

the Nuffield Foundation B1.A-2 in the purchaser’s school or college


Guidance AB1.B.1 Embryo selection is here to stay

Teaching notes
This activity recaps students’ understanding of Requirements (per student)
embryo selection. • Activity sheets AB1.B.1
Students should have met the terminology in an • coloured pens/pencils
earlier lesson. However, there is sufficient guidance
for students if they have not done so.

1 Definition of IVF: Paragraph 4 ‘fertilise the egg
outside the woman’s body’.
2 Description of choosing embryos: Text with
diagrams at bottom of article.
3 Fact: In 1989 scientists found the gene for cystic
fibrosis.
Speculation: some said we were close to a cure.
4 ‘This method throws away human beings.’
‘Embryos are a group of cells. They aren’t
conscious.’
5 eg Fact: ‘Fifteen years on we still don’t have
one.’
eg Speculation: ‘Soon they’ll be offering embryo
testing for features like eye colour or height.’
eg Opinion: ‘Couples that test the embryos for a
disease gene are just giving their children a
helping hand.’
6 The final sentence expresses a positive view of
PGD suggesting that the author is in favour of its
use.

the Nuffield Foundation B1.B-2 in the purchaser’s school or college


Guidance AB1.B.2 Inheriting gender

Teaching notes
This activity reinforces students’ understanding Requirements (per student)
of gender determination. • Activity sheet AB1.B.2

1
ovum
Sperm X X
cell
X XX XX
Y XY XY

2 a Reference to girls having two X
chromosomes. A faulty recessive allele will
not display its characteristic where there is a
normal dominant allele present on the other
X chromosome. Boys have only one X
chromosome, so a faulty recessive allele will
always be displayed.
b Haemophilia was recognised as an inherited
disease which could be passed on from one
generation of a family to the next.
c i Michael and Bob have haemophilia.
ii Lesley and Melissa are carriers of
haemophilia.
iii Sara, Leanne, and Kara may be carriers
of haemophilia.
iv Darren, Mark, Peter, and James are not
affected by haemophilia.

the Nuffield Foundation B1.B-3 in the purchaser’s school or college

Genes, inheritance and variation guidance

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