1. Key area 2 – DNA, Genes and Chromosomes
Cell Biology
National 4

2. Activity 1
Collect a card of Simpson characters.

3. Which of these Simpsons characters are related
Which of these Simpsons characters are related? How can you tell which characters are related even if you have never seen the Simpsons?

4. Learning Intentions
Explain inheritance is the passing on of characteristics from your parents
State genes are located on chromosomes in the nucleus.
Be able to state genes are made of DNA which carries the instructions to make proteins

5. Inheritance
Characteristics like hair colour, eye colour, nose shape and many others are passed down from your parents.
This is called INHERITANCE.
Inheritance video clip

6. How are characteristics inherited?
The genetic information to make all of these characteristics is found in every cell in your body.
It is hidden in the nucleus of each cell.

7. Nucleus contains chromosomes.
DNA contains sections called genes.
Chromosomes contain DNA.
Genes control inherited characteristics

8. The nucleus of a cell contains CHROMOSOMES that carry genetic information.
CHROMOSOMES are made from long, coiled molecules of DNA.
A GENE is a shorter region of DNA that carries the code for a particular characteristic or protein product.

9. Chromosomes Humans have 46 chromosomes in each nucleus.
23 of these came from the mother in the egg cell.
23 came from the father in the sperm cell.
During fertilisation the 2 sets combined to give the full set of 46 chromosomes.

11. Key area 2 - DNA, Genes and Chromosomes

12. Starter Answer the following sentences in your jotter.
What cell part controls the cells activities?
What structures inside the nucleus contain genetic information?
How many chromosomes do humans have?
What are chromosomes made of?

13. Answers
Nucleus
Chromosomes 46
DNA

14. Learning Intentions State DNA is a code.
State sections of DNA are called genes.
Describe the structure of DNA and what it is made of .

15. Genes
DNA is a big long code. Genes are sections of DNA. These sections contain codes which instruct our cells to make proteins which determine our characteristics.
Human inheritance video clip 1
Human inheritance video clip 2

16. Your DNA Your DNA is unique to you (unless you are an identical twin).
This is because sperm cells and egg cells are all genetically different, even from the same parents.
This is why you are not identical to your brother or sister.

17. Identical twins Identical twins have identical DNA.
This is because they came from the same fertilised egg which then split into two.
Non identical twins came from two eggs fertilised by two sperm, so they are genetically different.

18. How twins are formed

19. DNA Profiling Everyone’s DNA is unique.
It is because of this property that we are able to catch criminals using DNA samples.
DNA samples can also be used to identify the father of a child (paternity testing)
Activity 2 Watch the video clip and answer the questions in your booklet.
DNA Profiling

20. DNA Structure DNA is two strands joined together
DNA looks like a twisted ladder – double helix
We can untwist DNA and read its code

21. DNA
One small piece of DNA is made up of a sugar, a phosphate and a ‘base’

22. DNA There are 4 different bases A and T pair up G and C pair up A T G
What is a gene? Video clip

23. Base Pairing
ATCGTAGC TAGCATCG

24. Activity 3 – Crack the code
Using the letters A,T,G, and C, create a code 15 letters long.
Pass it to your partner to work out the corresponding strand.

25. Activity 4 Collect a DNA Origami sheet and instruction sheet.
Watch how to start then follow the instructions.

26. Today you have been able to:
State DNA is a code
State sections of DNA are called genes
Describe the structure of DNA and what it is made of
Create a model of DNA

27. KA 2 - DNA, Genes and Chromosomes
DNA Scientists
KA 2 - DNA, Genes and Chromosomes

28. Learning Intentions
Create a page describing the life and career of a scientist involved in the discovery of DNA.

29. Activity 5
Watch the following clip and answer the questions in your booklet.
Discovery of DNA

30. Activity 6 Your teacher will take you to an ICT room.
Select a DNA scientist and research their work and life. Choose from the following list:
Francis Crick
James Watson
Rosalind Franklin
Maurice Wilkins
Create a Facebook page for this scientist using the template for Word.

31. KA 2 - DNA, Genes and Chromosomes
Inherited Diseases
KA 2 - DNA, Genes and Chromosomes

32. Learning Intentions Explain some diseases can be inherited.
Discuss the ethical issues surrounding some inherited diseases.

33. Inherited diseases Watch the video clip about inherited diseases.

34. What protein is missing?
The following people suffer from a condition because they cannot correctly
code for a certain protein.
Do you know what protein they might be missing?
Simon is 11 years old. He was born with a condition called Albinism
(Albino) .
Simon’s body cannot make a protein that gives hair, skin and
eyes their unique colour. Therefore he has no colour in his eyes,
hair or skin.
What protein is he missing?
Suzy is 20 years old. She has suffered from a condition called diabetes since she was 7 years old. The symptoms of diabetes are tiredness and extreme thirst.
This condition means she can’t make a hormone (protein) that removes the sugar from her blood after she eats.
What is she missing?
Melanin
INSULIN

35. Activity 7 – ethical issues
Read the information on the cards and in groups discuss the ethics surrounding the issue.
Should everyone be able to have a test for this condition?
Should a parent tell their child that they might be carrying a genetic disorder?
Should parents be able to have their unborn child tested for the condition?
Should parents be able to terminate a pregnancy if the test result is positive?
Should multiple embryos be created, the embryos then tested for the condition and only healthy embryos selected and implanted into the woman?
Should genes be manipulated in an embryo to remove the faulty gene (designer babies)?
Should a sibling be used as a source of healthy cells or organs for their brother or sister?

36. Activity 7 – Research group work
Working in a group, one person should read out the information about the condition to the rest of the group.
Complete the task on the bottom of the card as a group exercise – one person should neatly write the letter, with others giving them ideas and guidance.