Topic Exploration Pack
Gene Technology
Topic Exploration Pack
Gene Technology
Instructions and answers for teachers
Mapping to specification level (Learning outcomes)
Introduction
Topic overview
Suggested activities
Useful sites
Learner Activity
Task 1 – Genetic engineering of human insulin
Instructions and answers for teachers
These instructions cover the learner activity section which can be found on page 15. This Topic Exploration Pack supports OCR GCSE (9–1)Gateway Science Biology A and the Twenty First Century Science Biology B qualifications.
When distributing the activity section to the learners either as a printed copy or as a Word file you will need to remove the teacher instructions section.
Version 11© OCR 2017
Mapping to specification level (Learning outcomes)
GCSE (9–1) Gateway Science Biology A/Combined Science A
B6.2d describe genetic engineering as a process which involves modifying the genome of an organism to introduce desirable characteristics
B6.2e describe the main steps in the process of genetic engineering
B6.2f explain some of the possible benefits and risks of using gene technology in modern agriculture
GCSE (9–1) Twenty First Century Science Biology B/Combined Science B
B1.3.2 describe genetic engineering as a process which involves modifying the genome of an organism to introduce desirable characteristics
B1.3.3 describe the main steps in the process of genetic engineering including:
•isolating and replicating the required gene(s)
•putting the gene(s) into a vector (e.g. a plasmid)
•using the vector to insert the gene(s) into cells
•selecting modified cells
Introduction
•Understand and explain the process of genetic engineering
•Understand and apply knowledge of alleles to investigate the risk of developing certain diseases
•Understand, explain and discuss the benefits and risks of using gene technology to modify genomes.
Topic overview
Objective 1
Developing our understanding of the human genome has helped us identify alleles associated with disease. Students are introduced to the concept of inheritance including carrying out a simple genetic cross and using it to calculate probability. This learning can then be used to explain how doctors use knowledge of the human genome to prescribe personalised medicine.
Objective 2
The specification introduces the students to the idea of modifying the genome in the process of genetic engineering. A wide variety of interesting examples of transgenic organisms can be used before looking at the more practical side of genetic engineering in farming contexts or eugenics.
Objective 3
Students look at the main steps in the process of genetic engineering. This will allow students to look at the practical side of the process including selecting required genes, inserting genes into vectors and the use of vectors to insert genes into target cells.
Objective 4
Students investigate and explain some of the possible benefits and risks associated with gene technology. Particular focus is placed on the concerns around the spread of inserted genes into the genomes of other organisms. Students discuss the ethical and moral consideration of the process and the implications it could have for future generations.
Suggested activities
Task 1 is designed to allow students to practice the techniques of genetic engineering. Students might find some of the concepts unfamiliar so by allowing them to carry out this activity it will allow them to assimilate ideas of the process along with posing questions on the topic.
Several questions can be asked about the procedure to make links to other parts of the specification including enzyme specificity and the factors affecting enzyme activity (B3.1.3), the use of aseptic techniques in culturing microorganisms (B2.3.2) and the difference between the replication of cells by mitosis(B4.3.1) and how bacteria multiply by binary fission.
Tasks 2a and 2b are designed to allow students to learn about genetic procedures in context.
Task 2a focuses on the inheritance of Huntington’s disease; a gene mutation affecting around 12 in every 100,000 of the UK’s population and the implications that genetic testing can have for individuals suffering with the disease.
Task 2b focuses on the techniques used to genetically test for chromosome mutations, in particular Down’s syndrome.
The tasks can be used as independent activities both in the classroom or as homework or as part of a group activity. The tasks can be used as the basis of a research activity to make links to other parts of the specification including what is a genome (B1.1.2), sex determination (B1.2.8) and how gametes are produced (B4.3.2).
Task 3 activities allow students to formulate their own opinions and challenge the opinions of others on genetic engineering.
Task 3a asks students to read statements about genetic engineering before cutting the statement out and putting it into either an ‘I agree’ column or an ‘I do not agree’ column. Students are then asked to justify their reasons for their choice.
Task 3b requires students to try to classify if the statements on genetic engineering cause an economic, social or ethical issue.
The economic, social and ethical considerations can be attempted individually before being discussed in pairs and then as a whole class. Links can be made to other parts of the specification including how communicable diseases spread (B2.1.3), plant defenses (B2.2.4) and food security (B6.4.3).
Task 1 –Genetic engineering of human insulin
- Suggest possible problems associated with using animal insulin to treat humans.
- It wasn’t until 1978 that insulin was produced by genetic engineering.
Explain why bacteria are ideal cells to use when carrying out this process.
- Explain why the enzyme used to remove the human insulin gene from the DNA is the same enzyme used to cut the bacterial plasmid.
- Genes can also be inserted into animals and plants.
Suggest reasons why scientists may want to do this.
- Trials have been carried out using genetic engineering to treat genetically inherited conditions.
Suggest how genetic engineering can be used to treat conditions where faulty genes have been inherited.
Task 2a – Genetic testing for Huntington’s disease
Huntington’s disease is a life limiting condition that is hereditary. It is a disorder of the central nervous system caused by a single faulty gene known as a gene mutation. If a patient has one copy of the gene, they will suffer from Huntington’s later in life and will die from the disease as there is no cure.
If one of the patient’s parents has Huntington’s disease, there is a 50% chance that any of their children will get the disease.
The uncertainty of living with the knowledge that there is a 50% chance that you carry the gene can be distressing but there is a DNA test available that can identify if a patient carries the gene.
However, not all people want to find out if they carry the gene. If the test is positive, it would be very distressing as there is no cure for the disease. It may also prove difficult for the patient to get a mortgage and life insurance to buy a house. Another thing to consider is that it creates moral issues if they decide to start a family.
People who decide to get the test are first advised to discuss the options with a counsellor, close family members and partners as it can have implications for them too.
Only patients over the age of 18 can make the decision about whether they want to be tested so parents cannot have their children tested to see if they have inherited the gene.
If a patient’s grandparent has Huntington’s disease but no other family member has been tested or shown symptoms of the disease, they are advised to think very carefully before considering the DNA test.
- Is Huntington's disease caused by a dominant or recessive gene?
- Why might a patient decide not to get the DNA test even if their parents do have it?
- Why might it prove difficult to get life insurance or mortgage if a patient has the test?
- Why do you think parents of a child who is under the age of 18 cannot get the test carried out on the child?
- Why might knowing about having the gene cause a moral issue if they decide to start a family?
- Why is it advisable to carefully consider taking a DNA test if a grandparent has the condition but no other family members have been tested or shown symptoms of the disease?
- Why do you think people decide to get tested?
- Do you think this test should be available?
Task 2b – Genetic testing for Down’s syndrome
Down’s syndrome is a genetic condition caused by a chromosome mutation. In people with Down's syndrome, all or some of the cells in their bodies contain 47 chromosomes, as there is an extra copy of chromosome 21. This is known as trisomy 21.
Usually, cells contain 46 chromosomes. A child inherits 23 from the mother and 23 from the father but in Down’s syndrome the child inherits 24 chromosomes from one parent due to a mistake made during the production of their sex cells (sperm or egg). The additional genetic material causes physical and developmental characteristics associated with Down's syndrome and does reduce their life expectancy to 60 years.
The main factor that increases the chance of having a baby with Down's syndrome is the age of the woman when she becomes pregnant. An increase in age of the woman increases the risk of having a child with Down’s syndrome as below:
•20 years of age has a risk of one in 1,500
•30 years of age has a risk of one in 800
•35 years of age has a risk of one in 270
•40 years of age has a risk of one in 100
•45 years of age has a risk of one in 50 or greater.
However, babies with Down's syndrome are born to mothers of all ages.
The uncertainty of going through pregnancy with the knowledge that there is a chance that your child may have a chromosome mutation can be distressing. Pregnant mothers are offered the opportunity to have a test to see if they have a high chance of having a child with a genetic mutation such as Down’s syndrome.
The test involves a procedure called an ‘amniocentesis’ where a large needle is inserted into the abdomen of the female and into the fluid surrounding the baby. A sample of the fluid is then tested to see if the cells of the baby are ‘trisomy’. This is usually done between 15 and 20 weeks of pregnancy. However, not all people want to have an amniocentesis to find out if their child has Down’s syndrome as it creates a moral issue if they decide to continue the pregnancy.
The diagram below shows the result of an amniocentesis where trisomy 21 can be seen – there are three copies of chromosome 21 instead of two. This picture is called a karyotype.
- What risks could there be with having an amniocentesis?
- Why do you think it is not recommended to get the test done before 15 weeks of pregnancy?
- Why do you think people decide to get tested?
- Why might a pregnant mother decide not to have an amniocentesis?
- Why might it cause a moral issue if they continue with the pregnancy?
- Individuals suffering from Down’s syndrome are often infertile and cannot have children of their own. Why do you think this is?
- Do you think this test should be available?
Task 3a – Making choices on Genetic engineering
Genetic engineering divides people’s opinions. Some people agree with it, some people only agree on some of its uses and some are totally against it.
Uses of genetic engineering that divides opinion are often Genetically Modified (GM) crops and GM animals.
Divide your exercise book into 3 columns with headings, the first being ‘yes I agree’, the second being ‘no I do not agree’ and the third column ‘reasons’. Cut out each of the statements below and stick them into one of the first two columns based on whether you agree or disagree with the statement. In the third column try to come up with a reason why you agree or a reason why you do not agree for each statement.
Students can put the statements in either column but they need to provide a reason for their option.
Modified animals could become the new ‘wonder pet’ and make loads of money / •‘Wonder pets’ could make a lot of money
•Selective breeding can go some way to getting a wonder pet
GM crops could escape and breed with weeds making ‘super weeds’ / •This is unlikely and would not cause any damage
•It might make a weed that we cannot control with pesticides
Modified animals can be made disease resistant / •This would reduce the cost of food as less animals get ill
•We already have vaccinations and antibiotics to stop disease
Parents could pick genes for their babies making ‘Designer babies’ / •This would stop genetic diseases existing
•It could be used to get height, skin colour, eye colour changed
GM crops can be made to taste better and be bigger / •Better tasting food can be sold for more money
•If food tastes good already why try to improve it
GM crops can be pest resistant so will not require expensive pesticides / •This would reduce the impact on the surrounding environment
•Biological pest control could be used like ladybirds
GM crops can be made that will grow in very dry environments / •This can feed people in drought regions of the world
•Could water wells be installed with the money
The more we modify animals the more we learn to treat human conditions / •This could be used to help cure human genetic diseases
•Humans and animals are different so it will not always work
We do not know what GM crops could do to us if we eat them / •If the inserted gene comes from a food there cannot be much risk
•Could the inserted gene be inserted into us
Task 3b – The issues behind Genetic engineering
Many of the issues fall into more than one category and a good explanation could put the issue into all three categories. Challenge students on the choices and ask them to explain their reasoning for each.
The issue / Economic / Social / EthicalModified animals could become the new ‘wonder pet’ and make loads of money / /
GM crops could escape and breed with weeds making ‘super weeds’ / /
Modified animals can be made disease resistant / / /
Parents could pick genes for their babies making ‘Designer babies’ / /
GM crops can be made to taste better and be bigger / /
GM crops can be pest resistant so will not require expensive pesticides /
GM crops can be made that will grow in very dry environments / /
The more we modify animals the more we learn to treat human conditions / /
We do not know what GM crops could do to us if we eat them / /
Useful sites
Task 1
Gene therapy
Task 2
Amniocentesis
Huntington’s disease
Down’s syndrome
Task 3
GM foods
Further study
Cloning
Version 11© OCR 2017
Topic Exploration Pack
Gene Technology
Learner Activity
Task 1 – Genetic engineering of human insulin
The process of genetic engineering involves taking a gene from one organism and inserting it into another. The activity below is a cut and stick task showing how an insulin gene from a human cell is removed and inserted into bacteria which will produce the insulin for us.
/ Bacteria multiply by binary fission / / DNA plasmid is cut with same enzyme/ Insulin gene is inserted into plasmid by a second enzyme / / Insulin gene is cut out of the human DNA using an enzyme
/ Bacterial cell containing DNA plasmid / / Human cell containing insulin gene
/ Plasmid is taken up by bacteria / / Insulin produced by the bacteria can be removed
Version 11© OCR 2017
In the early part of the 19th century, patients suffering from diabetes often died in childhood as there was no known treatment. In 1921, a young surgeon named Frederick Banting and his assistant Charles Best discovered that insulin from animals could be used to treat humans.
- Suggest possible problems associated with using animal insulin to treat humans.
- It wasn’t until 1978 that insulin was produced by genetic engineering.
Explain why bacteria are ideal cells to use when carrying out this process.
- Explain why the enzyme used to remove the human insulin gene from the DNA is the same enzyme used to cut the bacterial plasmid.
- Genes can also be inserted into animals and plants.
Suggest reasons why scientists may want to do this.
- Trials have been carried out using genetic engineering to treat genetically inherited conditions.
Suggest how genetic engineering can be used to treat conditions where faulty genes have been inherited.
Task 2a – Genetic testing for Huntington’s disease
Huntington’s disease is a life limiting condition that is hereditary. It is a disorder of the central nervous system caused by a single faulty gene known as a gene mutation. If a patient has one copy of the gene, they will suffer from Huntington’s later in life and will die from the disease as there is no cure.
If one of the patient’s parents has Huntington’s disease, there is a 50% chance that any of their children will get the disease.
The uncertainty of living with the knowledge that there is a 50% chance that you carry the gene can be distressing but there is a DNA test available that can identify if a patient carries the gene.