1. 3.5 Genetic modification and biotechnology
Understanding:
Gel electrophoresis is used to separate proteins of fragments of DNA according to size
PCR can be used to amplify small amounts of DNA
DNA profiling involves comparison of DNA
Genetic modification is carried out by gene transfer between species
Clones are groups of genetically identical organisms, derived from a single original parent cell
Many plant species and some animal species have natural methods of cloning
Animals can be cloned at the embryo stage by breaking up the embryo into more than one group of cells
Methods have been developed for cloning adult animals using differentiated cells
Skills:
Design of an experiment to assess one factor affecting the rooting of stem cuttings
Analysis of examples of DNA profiles
Analysis of data on risks to monarch butterflies of Bt crops
Applications:
Use of DNA profiling in paternity and forensic investigations
Gene transfer to bacteria with plasmids using restriction endonucleases and DNA ligase
Assessment of the potential risks and benefits associated with genetic modification of crops
Production of cloned embryos by somatic cell nuclear transfer
Nature of science:
Assessing risks associated with scientific research: scientists attempt to assess the risks associated with genetically modified crops or livestock

3. Polymerase Chain Reaction (PCR)
Amplify small amounts of DNA
Just need a single molecule of DNA to make millions of copies
Able to study DNA without using up the whole sample
DNA from fossils
DNA from crime scene (hair, semen or blood)
Understanding:
PCR can be used to amplify small amounts of DNA

4. Cover work: Polymerase Chain Reaction (PCR)
Answer these questions
What are the ingredients for PCR?
What are primers?
Why must the mixture be heated/cooled to about 95°C? 55-60°C? 72°C?
Understanding:
PCR can be used to amplify small amounts of DNA

5. Polymerase Chain Reaction (PCR)
1. Template DNA, DNA primers, Deoxynucleotide triphosphates, thermophilic polymerase with a buffer
2. Primers start the chain reaction
3. 95 = DNA strands separate as hydrogen bonds break
55-60 = Primers bind to single DNA strands
75 = optimum temperature for DNA polyermase enzyme
Understanding:
PCR can be used to amplify small amounts of DNA

6. Gel Electrophoresis Separate proteins according to size
In an electric field
Samples placed into wells in a gel
Electrical field applied
Charged molecules move through the gel
Small fragments move faster than large ones
Understanding:
Gel electrophoresis is used to separate proteins of fragments of DNA according to size

7. Cover work: Gel Electrophoresis
Go to:
Answer the following questions:
What is the gel made up of?
What is the purpose of the buffering solution that the gel is immersed in?
Why are known DNA fragment lengths/size standards needed?
How does the gel separate DNA strands of different lengths?
Understanding:
Gel electrophoresis is used to separate proteins of fragments of DNA according to size

8. Gel Electrophoresis Powdered agarose, buffer (Jell-o)
Salt water solution that allows electrical charges to move through the gel
Compare your bands to bands of known length to help you identify the length of DNA
DNA moves through gel repelled by negative charge – smaller moves further away
Understanding:
Gel electrophoresis is used to separate proteins of fragments of DNA according to size

9. DNA profiling Sample of DNA obtained
Sequences selected and copied by PCR
Copied DNA split into fragments using enzymes
Fragments separated using gel electrophoresis
Produces a pattern of bands that is always the same with DNA from an individual
Compare profiles of individuals to see which bands are similar or different
Understanding:
DNA profiling involves comparison of DNA

10. Compare DNA at a crime scene with suspects DNA

11. Paternity Tests Men claim they are not the father
Mother has multiple partners and isn’t sure
Child wishes to prove they are an heir
Applications:
Use of DNA profiling in paternity and forensic investigations
Skills:
Analysis of examples of DNA profiles

13. Genetic Modification Transfer of genes between species
Genetic code is universal = amino acid sequences translated from genetic code is unchanged
Same polypeptide is produced
Understanding:
Genetic modification is carried out by gene transfer between species

14. Genetic Modification Gene for making human insulin to bacteria
Goats produce milk that contains spider silk
Many GM crops
Understanding:
Genetic modification is carried out by gene transfer between species

15. Salmon grows twice as fast
Genetic Modification
Salmon grows twice as fast
Understanding:
Genetic modification is carried out by gene transfer between species

16. Bananas that contain a vaccine for a disease
Genetic Modification
Bananas that contain a vaccine for a disease
Understanding:
Genetic modification is carried out by gene transfer between species

17. Genetic Modification Cows with 25% less methane
Less impact on the environment
Understanding:
Genetic modification is carried out by gene transfer between species

18. Involves the use of plasmids, DNA ligase and restriction endonucleases
Gene Transfer
Involves the use of plasmids, DNA ligase and restriction endonucleases
Applications:
Gene transfer to bacteria with plasmids using restriction endonucleases and DNA ligase
Understanding:
Genetic modification is carried out by gene transfer between species

21. Ligase sticks end together
Restriction enzymes cut both gene and plasmid (produce the same ‘sticky ends’)
Ligase sticks end together

23. Multiply bacteria containing gene

24. Separate and purify human insulin
Human insulin can then be used by diabetic patients

25. Finish off... PCR questions Gel Electrophoresis questions
Check your cuttings experiment - is anything happening yet?
Kognity topic 5 questions
Next lesson is topic 10 (HL)

26. What is a clone?
A clone is genetically identical to its “parent” (single original parent)
Understanding:
Clones are groups of genetically identical organisms, derived from a single original parent cell

27. Types of reproduction SEXUAL Genetically different offspring ASEXUAL
Genetically identical offspring
Understanding:
Many plant species and some animal species have natural methods of cloning

28. Sexual Reproduction HUMANS GAMETES Sperm cell: Egg cell:
Each gamete contains 23 single chromosomes
Half the number of that in a normal cell (23 pairs)
These are haploid cells
Understanding:
Many plant species and some animal species have natural methods of cloning

29. Sexual Reproduction FERTILISATION Gametes fuse together
Form a cell with 23 pairs of chromosomes
This is a Diploid cell
Offspring inherits features from both parents
Variation in offspring

30. Advantages: Sexual Variation in offspring means they are able to
Adapt to surroundings
Evolve
Understanding:
Many plant species and some animal species have natural methods of cloning

31. Asexual Reproduction
An ordinary cell can make a new cell by dividing in two
New cell has exactly the same information as parent cell
No fertilisation between male and female gametes
Some plants and bacteria produce offspring asexually (some animals do too when no males around)
Understanding:
Many plant species and some animal species have natural methods of cloning

32. Advantages: Asexual Very quick
Bacteria can produce offspring in 20 mins
If already adapted to habitat – good to be identical
Understanding:
Many plant species and some animal species have natural methods of cloning

33. Break up embryo into more than one group of cells
Embryos
Break up embryo into more than one group of cells
All cells in an early animal embryo are able to develop into any type of tissue
Understanding:
Animals can be cloned at the embryo stage by breaking up the embryo into more than one group of cells

34. Cloning Animal Embryos
Sometimes this happens naturally
Can also be done artificially
Understanding:
Animals can be cloned at the embryo stage by breaking up the embryo into more than one group of cells

35. Able to ensure they have desired characteristics
Cloning Adults
Harder than cloning embryos as cells have already differentiated into different tissue cells
Able to ensure they have desired characteristics
Understanding:
Methods have been developed for cloning adult animals using differentiated cells

36. Dolly the Sheep Applications:
Production of cloned embryos by somatic cell nuclear transfer

37. A tale of somatic cell nuclear transfer
Dolly the Sheep
A tale of somatic cell nuclear transfer

38. What’s a somatic cell???

39. Normal body cell Diploid nucleus 23 pairs of chromosomes

40. Her name is not important
Once upon a time…
There was a Finn Dorset Ewe
Her name is not important

41. Cells were taken from her udders These were grown in a lab

42. Genes made to become inactive No longer on a path of differentiation

43. Then we meet the Scottish Blackface Ewe
Unfertilized eggs taken from her ovaries, nucleus removed

44. So we have these two types of cells
Udder cells with inactive genes
Unfertilized egg cells with no nucleus

45. 10% of fused cells turned into an embryo
Electric pulse used to fuse the two cells together
10% of fused cells turned into an embryo

46. 7 day old embryos injected into surrogate mothers ewes
1/29 was successful

47. (with the one with the udders)
Dolly was the spitting image of the Finn Dorset Ewe
(with the one with the udders)
THIS WAS DOLLY

50. Plant cuttings experiment
Investigating factors affecting the rooting of stem cuttings: in groups
Short lengths of stem that are used to clone plants artificially
Roots develop from stem = independent new plant
Design your experiment which we will complete next time we are in a lab
Hypothesis and explanation
Independent variable, dependent variable, control variable
Method
What could your independent variable be?
Length of stem
How many leaves
Size of leaves
Water or compost
Cut above or below node
Temperature of air
Plastic bag over cuttings
Skills:
Design of an experiment to assess one factor affecting the rooting of stem cuttings