1. Genetics and Inheritance Alleles and Appearance

2. Alleles and Appearance Diploid zygote Haploid gametes

7. Alleles and Appearance T T T t t t Tall Tall Dwarf Dwarf = Recessive (t) Tall = Dominant (T)

15. Genetics and Inheritance The monohybrid cross

20. The Monohybrid Cross Filial = son / daughter X P (parents) X F 1 (first filial generation) F 2 (second filial generation)

21. The Monohybrid Cross BB BB BB BB BB BB BB BB Gametes all ‘B’ Gametes all ‘B’ X P X F 1 F 2

23. The Monohybrid Cross All offspring (F 1 ) bb bb bb Parents x bb bb x Second generation (F 2 ) bb Gametes all b b Gametes all b b

24. The Monohybrid Cross X P X F 1 F 2

26. The Monohybrid Cross bb BB Bb Bb Bb BB bb Bb B B b b b b B B X P F 2 X F 1

35. The Monohybrid Cross BB or Bb?

36. The Monohybrid Cross B B b b Bb Bb Bb Bb All offspring: black B b b b Bb bb Bb bb Ratio = Black : White 1 : 1 X BB bb X Bb bb

38. Genetics and Inheritance Co-dominance

43. Genetics and Inheritance Polygenic Inheritance

47. Discontinuous data Continuous data Distinct data can be presented as a bar graph. Ranges of data can be presented as a histogram or line graph. No. of pupils Tongue rolling ability Roller Non-roller Pea seed shoot lengths (mm) No. of seeds 1-5 6-10 11-15 16-20 21-25

49. Genetics and Inheritance Organisms in genetic experiments

52. Using Drosophila Notes The steps involved in setting up a cross to study the colour of the abdomen in Drosophila flies Parents must be true breeding to ensure dominant alleles are not hiding recessive alleles. 1. Parents are chosen, one with a grey body and the other with an ebony body. Notes Steps

53. Using Drosophila Notes This produces the F 1 generation. 2. Breed the parents. Notes Steps

54. Using Drosophila Notes This identifies the dominant allele. 3. The F 1 phenotype is observed. Notes Steps

55. Using Drosophila Notes This produces the F 2 generation. 4. The F 1 generation is self-crossed. Notes Steps

56. Using Drosophila Notes This allows the phenotype ratio to be calculated. 5. The F 2 generation is examined and the number of each phenotype counted. Notes Steps

57. Using Drosophila Notes This improves the reliability of the results. 6. The experiment is repeated. Notes Steps