1. Fig. 10-1a, p.152

2. Fig. 10-1b, p.152 ATP

3. p.153

4. Fig. 10-2, p.154

5. a Garden pea flower, cut in half. Sperm form in pollen grains, which originate in male floral parts (stamens). Eggs develop, fertilization takes place, and seeds mature in female floral parts (carpels). b Pollen from a plant that breeds true for purple flowers is brushed onto a floral bud of a plant that breeds true for white flowers. The white flower had its stamens snipped off. This is one way to assure cross-fertilization of plants. c Later, seeds develop inside pods of the cross- fertilized plant. An embryo within each seed develops into a mature pea plant. d Each new plant’s flower color is indirect but observable evidence that hereditary material has been transmitted from the parent plants. Fig. 10-3, p.154 carpelstamen

6. b A gene locus (plural, loci), the location for a specific gene on a chromosome. Alleles are at corresponding loci on a pair of homologous chromosomes d Three pairs of genes (at three loci on this pair of homologous chromosomes); same thing as three pairs of alleles. Fig. 10-4, p.155 a A pair of homologous chromosomes, both unduplicated. In most species, one is inherited from a female parent and its partner from a male parent. c A pair of alleles may be identical or not. Alleles are represented in the text by letters such as D or d.

7. fertilization produces heterozygous offspring meiosis II meiosis I (chromosomes duplicated before meiosis) Homozygous dominant parent Homozygous recessive parent (gametes) Fig. 10-5, p.156

8. Trait Studied Dominant Form Recessive Form F 2 Dominant- to-Recessive Ratio Seed shape Seed color Pod shape Pod color Flower color Flower position Stem length 2.98:1 3.01:1 2.95:1 2.82:1 3.15:1 3.14:1 2.84:1 787 tall 277 dwarf 651 long stem 207 at tip 705 purple 224 white 152 yellow428 green 299 wrinkled882 inflated 6,022 yellow2,001 green 5,474 round 1,850 wrinkled Fig. 10-6, p.156

9. female gametes male gametes Fig. 10-7a, p.157 a From left to right, step-by-step construction of a Punnett square. Circles signify gametes. A stands for a dominant allele and a for a recessive allele at the same gene locus. Offspring genotypes are indicated inside the squares. A AA A A AAA A A Aa aa a a a a a a a a

10. Fig. 10-7b, p.157 A AA Aa a A a aa Aa True-breeding homozygous recessive parent plant F 1 offspring b Cross between two plants that breed true for different forms of a trait. True-breeding homozygous dominant parent plant

11. Fig. 10-7c, p.157 A Aa A a a AAAa aaAa F 2 offspring Heterozygous F 1 offspring Heterozygous F 1 offspring c Cross between heterozygous F1 offspring. aa AA

12. p.165 the expected phenotypic ratio of 3:1 (dominant) (recessive) AA Aa aa Aa A A a a

13. Fig. 10-9, p.159 parent homozygous recessive for white flowers, short stems Gametes at fertilization parent homozygous dominant for purple flowers, tall stems Meiosis, gamete formation in true-breeding parent plants Possible genotypes resulting from a cross between two F 1 plants: meiosis, gamete formation All F 1 plants are AaBb heterozygotes with purple flowers and tall stems. meiosis, gamete formation

14. Fig. 10-10, p.160 Phenotypes (Blood type): Genotypes: AABBO or ABAOBOOO BBAA or

15. Fig. 10-11, p.160 Cross two of the F1 plants, and the F2 offspring will show three phenotypes in a 1:2:1 ratio: homozygous parent (RR) homozygous parent (rr) heterozygous F1 offspring (Rr) x RRRr rr

16. Fig. 10-13, p.161 EBEbeBeb EB Eb eB eb EeBb black EeBB black EEBb black EEBB black EEBb black EeBB black EeBb black Eebb chocolate EeBb black EEbb chocolate EeBb black Eebb chocolate eeBB yellow eeBb yellow eebb yellow eeBb yellow

17. Fig. 10-16, p.163

18. p.164

19. Fig. 10-19a, p.164 Range of values for the trait This red graph line of the range of variation for a trait in a population plots out as a bell-shaped curve. Such curves indicate continuous variation in a population. Number of individuals with a measurable value for the trait

20. Fig. 10-19c, p.164

21. Fig. 10-20a-b, p.166