iGCSE Biology Section 5 lesson 2

1. iGCSE Biology Section 5 lesson 2

2. Content Section 5 Uses of biological resources • Food production • Selective breeding • Genetic modification (genetic engineering) • Cloning

3. Content b) Selective breeding Lesson 2 b) Selective breeding c) Genetic modification 5.10 understand that plants with desired characteristics can be developed by selective breeding 5.11 understand that animals with desired characteristics can be developed by selective breeding. c) Genetic modification 5.12 describe the use of restriction enzymes to cut DNA at specific sites and ligase enzymes to join pieces of DNA together 5.13 describe how plasmids and viruses can act as vectors, which take up pieces of DNA, then insert this recombinant DNA into other cells 5.14 understand that large amounts of human insulin can be manufactured from genetically modified bacteria that are grown in a fermenter 5.15 evaluate the potential for using genetically modified plants to improve food production (illustrated by plants with improved resistance to pests) 5.16 understand that the term ‘transgenic’ means the transfer of genetic material from one species to a different species.

4. Selective breeding Selective breeding is a method used for many years by farmers and growers to improve crops and yields. For example, milk production or disease resistance.

5. Selective breeding • Selective breeding aims to improve the features of a species. • Eg. To produce leaner pigs: • Select pigs with the least fat and mate them • Select the best of the offspring and mate these • Continue selecting and breeding over many generations.

6. Selective breeding Disease-resistant wheat has also been developed by cross – breeding wheat plants with disease resistance and wheat plants with a high yield.

7. Selective breeding Disease-resistant wheat has also been developed by cross – breeding wheat plants with disease resistance and wheat plants with a high yield. The stalk of the wheat plant has also been developed by selective breeding to make it shorter and stronger – helps with harvesting.

8. Selective breeding Milk yield in dairy cattle has been increased by selecting bulls from high yield herds and breeding them with cows that have the best milk production

9. Selective breeding Milk yield in dairy cattle has been increased by selecting bulls from high yield herds and breeding them with cows that have the best milk production

10. Other examples of selective breeding ROSES –bred for colour, shape and scent.

11. SHEEP – bred for quality wool and lamb production Other examples of selective breeding ROSES –bred for colour, shape and scent.

12. SHEEP – bred for quality wool and lamb production Other examples of selective breeding APPLES – bred for colour, taste and texture ROSES –bred for colour, shape and scent.

13. SHEEP – bred for quality wool and lamb production Other examples of selective breeding DOGS – bred for speed and endurance APPLES – bred for colour, taste and texture ROSES –bred for colour, shape and scent.

14. SHEEP – bred for quality wool and lamb production Other examples of selective breeding DOGS – bred for speed and endurance CATS – bred for best of breed shows APPLES – bred for colour, taste and texture ROSES –bred for colour, shape and scent.

15. SHEEP – bred for quality wool and lamb production Other examples of selective breeding DOGS – bred for speed and endurance CATS – bred for best of breed shows APPLES – bred for colour, taste and texture LINSEED – bred for oil production ROSES –bred for colour, shape and scent.

16. Selective breeding Advantages: Produces an organism with the right features for a particular function. Produces a more efficient and economically viable process for farming and horticulture.

17. Selective breeding Advantages: Produces an organism with the right features for a particular function. Produces a more efficient and economically viable process for farming and horticulture. Disadvantages: Reduced number of alleles in the population. Reduced variation, so unable to respond to environmental change. Can lead to other unexpected health problems.

18. Genetic Modification

19. Genetic Modification Genetic Modification Genetic modification (GM) is the use of modern biotechnology to change the genes of an organism

20. Genetic Modification Why GM?

21. Genetic Modification Why GM? To improve crop yields, eg. larger tomatoes, more oil from linseed plants

22. Genetic Modification Why GM? To improve resistance to pests or herbicides, eg. Pyrethrum To improve crop yields, eg. larger tomatoes, more oil from linseed plants

23. Genetic Modification Why GM? To improve resistance to pests or herbicides, eg. Pyrethrum To improve crop yields, eg. larger tomatoes, more oil from linseed plants To improve the shelf-life of fast ripening crops such as tomatoes

24. Genetic Modification Why GM? To improve resistance to pests or herbicides, eg. Pyrethrum To improve crop yields, eg. larger tomatoes, more oil from linseed plants To harness the cell chemistry of an organism, eg. human insulin To improve the shelf-life of fast ripening crops such as tomatoes

25. Genetic Modification Genes are often transferred at an early stage of development (in both animals and plants) so they develop with the required characteristics GM Stuffed Dog (not really)

26. Genetic Modification Genes are often transferred at an early stage of development (in both animals and plants) so they develop with the required characteristics Characteristics can then be passed onto the offspring if the organism reproduces asexually, or is cloned. GM Stuffed Dog (not really)

27. Genetic Modification “describe the use of restriction enzymes to cut DNA at specific sites and ligase enzymes to join pieces of DNA together”

28. Genetic Modification How do we change the genes of an organism?

29. Genetic Modification How do we change the genes of an organism? That’s a really good question – let’s start with an example

30. Genetic Modification A hormone secreted by the pancreas, essential for the control of blood glucose. The production of human insulin by genetic engineering.

31. Genetic Modification A hormone secreted by the pancreas, essential for the control of blood glucose. The production of human insulin by genetic engineering. A Type 1 diabetes patient needs insulin injections to survive.

32. Genetic Modification A hormone secreted by the pancreas, essential for the control of blood glucose. Insulin medications were originally taken from cows, pigs or salmon. The production of human insulin by genetic engineering. A Type 1 diabetes patient needs insulin injections to survive.

33. Genetic Modification A hormone secreted by the pancreas, essential for the control of blood glucose. Insulin medications were originally taken from cows, pigs or salmon. The production of human insulin by genetic engineering. A Type 1 diabetes patient needs insulin injections to survive. Human insulin first synthesised by genetic engineering in 1978.

34. Genetic Engineering – The Process Chromosome Human cell Part of a human chromosome Human insulin gene

35. Genetic Engineering – The Process Chromosome The gene for insulin production is ‘cut out’ of the human chromosome using restriction enzymes Human cell Part of a human chromosome Human insulin gene

36. Genetic Engineering – The Process Restriction enzymes, found naturally in bacteria, can be used to cut chromosome (DNA) fragments at specific points. Chromosome The gene for insulin production is ‘cut out’ of the human chromosome using restriction enzymes Human cell Part of a human chromosome Human insulin gene

37. Genetic Engineering – The Process Chromosome The gene for insulin production is ‘cut out’ of the human chromosome using restriction enzymes Human cell Part of a human chromosome

38. Genetic Engineering – The Process Bacteria are prokaryotic micro- organisms. They do not have a distinct cell nucleus Bacterium Bacterial DNA Plasmid = small DNA molecule, separate from the chromosomal DNA

39. Genetic Engineering – The Process Genetic Engineering – The Process Another restriction enzyme is used to cut open a ring of bacterial DNA.

40. Genetic Engineering – The Process Genetic Engineering – The Process Another restriction enzyme is used to cut open a ring of bacterial DNA. Other enzymes (ligase enzymes) are used to insert the piece of human DNA into the plasmid.

41. Genetic Engineering – The Process Genetic Engineering – The Process Another restriction enzyme is used to cut open a ring of bacterial DNA. Ligase enzymes are enzymes that catalyze reactions which make bonds to join together (ligate) smaller molecules to make larger ones. Other enzymes (ligase enzymes) are used to insert the piece of human DNA into the plasmid.

42. Genetic Engineering – The Process Plasmid now reinserted into a bacterium which starts to divide rapidly. VAT

43. Genetic Engineering – The Process As it divides it replicates the plasmid, and very soon there are millions of them, each with the code to make insulin. VAT

44. Genetic Engineering – The Process Commercial quantities of insulin are then produced. VAT

45. Genetic Engineering – The Process The vector (the carrier) may be a virus rather than a bacterial plasmid. The viral vector is also known as a virion.

46. Genetic Engineering – The Process The viral vector is able to transport the DNA directly into the nucleus of another cell. The vector (the carrier) may be a virus rather than a bacterial plasmid. The viral vector is also known as a virion.

47. Genetic Engineering – The Process The viral vector is able to transport the DNA directly into the nucleus of another cell. After insertion of the DNA the protein is then produced using the cells’ own mechanism. The vector (the carrier) may be a virus rather than a bacterial plasmid. The viral vector is also known as a virion.

48. Genetic Engineering – The Process Human insulin was the first commercially available protein produced by recombinant DNA technology.

49. Genetic Engineering – The Process Recombinant DNA is the general name for taking a piece of one DNA strand and combining it with another strand of DNA. Human insulin was the first commercially available protein produced by recombinant DNA technology.

50. Genetic Engineering – The Process Large amounts of human insulin can be manufactured from genetically modified bacteria that are grown in a fermenter