1. Fig. 9-1, p. 156

2. Fig. 9-2, p. 157 Genes occur in pairs on homologous chromosomes. The members of each pair of genes may be identical in DNA sequence, or they may be slightly different (alleles).

3. Fig. 9-3, p. 157 1 2 3

4. Fig. 9-4, p. 158 DNA replication meiosis I meiosis II (gametes) (zygote)

5. Fig. 9-4, p. 158 DNA replication meiosis I meiosis II (gametes) (zygote) Stepped Art

6. Fig. 9-5, p. 159

7. Fig. 9-5a, p. 159 female gametes male gametes A Making a Punnett square. The possible parental gametes are listed on the top and left sides of the grid (in circles). Each square is filled in with the combination of alleles that would result if the gametes in the corresponding row and column met up.

8. Fig. 9-5b, p. 159 offspring Heterozygous parent B A Punnett square shows that the ratio of dominant- to-recessive phenotypes among offspring of a monohybrid cross is about 3:1 (3 purple to 1 white).

9. Fig. 9-5b, p. 159 offspring Heterozygous parent B) A Punnett square shows that the ratio of dominant-to-recessive phenotypes among offspring of a monohybrid cross is about 3:1 (3 purple to 1 white). Stepped Art female gametes male gametes A) Making a Punnett square. The possible parental gametes are listed on the top and left sides of the grid (in circles). Each square is filled in with the combination of alleles that would result if the gametes in the corresponding row and column met up.

10. Fig. 9-6, p. 160 C) Two nuclei form with each scenario, so there are a total of four possible combinations of parental chromosomes in the nuclei that form after meiosis I. meiosis I D) Thus, when sister chromatids separate during meiosis II, the gametes that result have one of four possible combinations of maternal and paternal chromosomes. meiosis II gamete genotype: A) This example shows just two pairs of homologous chromosomes in the nucleus of a diploid (2n) reproductive cell. Maternal and paternal chromosomes, shown in pink and blue, have already been duplicated. B) Either chromosome of a pair may get attached to either spindle pole during meiosis I. With two pairs of homologous chromosomes, there are two different ways that the maternal and paternal homologues can get attached to opposite spindle poles. or Stepped Art

11. Fig. 9-7, p. 161

12. Fig. 9-7a, p. 161 parent plant homozygous for purple flowers and long stems parent plant homozygous for white flowers and short stems dihybrid four types of gametes

13. Fig. 9-7b, p. 161

14. Stepped Art parent plant homozygous for purple flowers and long stems parent plant homozygous for white flowers and short stems 2) dihybrid 3) four types of gametes

15. Fig. 9-8, p. 162

16. Fig. 9-9, p. 163 Genotypes: Phenotypes (blood type): AABBO

17. Fig. 9-10a, p. 163 homozygous parent (RR) x homozygous parent (rr) heterozygous offspring (Rr) A Cross a red-flowered with a white-flowered plant, and all of the offspring will be pink heterozygotes.

18. Fig. 9-10b, p. 163 B If two of the heterozygotes are crossed, the phenotypes of the resulting offspring will occur in a 1:2:1 ratio.

19. Fig. 9-11, p. 164

20. Fig. 9-12, p. 165

21. Fig. 9-12a, p. 165

22. Fig. 9-12b, p. 165

23. Fig. 9-14, p. 166 60 Height (centimeters) 000 A Plant grown at high elevation (3,060 meters above sea level) B Plant grown at mid-elevation (1,400 meters above sea level) C Plant grown at low elevation (30 meters above sea level)

24. marriage/mating female male offspring individual showing trait being studied sex not specified generation A) Standard symbols used in pedigrees B) A pedigree for polydactyly, which is characterized by extra fingers, toes, or both. The black numbers signify the number of fingers on each hand; the blue numbers signify the number of toes on each foot. Fig. 9-15, p. 167 *Gene not expressed in this carrier. Stepped Art

25. Table 9-1, p. 168

26. Fig. 9-16a, p. 168 normal mother affected father meiosis and gamete formation affected child normal child disorder-causing allele (dominant)

27. Fig. 9-16b, p. 168

28. Fig. 9-17, p. 169

29. Fig. 9-17a, p. 169 carrier mothercarrier father meiosis and gamete formation affected child carrier child normal child disorder-causing allele (recessive)

30. Table 9-2, p. 169

31. Table 9-3, p. 170

32. Fig. 9-18 (top), p. 170

33. Fig. 9-18 (a-d), p. 170

34. Fig. 9-19, p. 171

35. Table 9-4, p. 171

36. Fig. 9-20a, p. 172 Metaphase IAnaphase ITelophase IMetaphase IIAnaphase IITelophase II

37. Fig. 9-20b, p. 172

38. Stepped Art Metaphase I Anaphase I Telophase I Metaphase II Anaphase II Telophase II

39. Fig. 9-20c, p. 172

40. p. 174

41. Fig. 9-23, p. 175

42. Fig. 9-24, p. 177