• Name Date Period Genetics Practice Problems #3 – Monohybrid Problems Worksheet 1 Directions: Using the table and rules below, complete Table 2: If you use a separate sheet of paper to set up and solve your problems, attach work showing Punnett Squares to receive credit. No Punnett squares – No credit Rules for writing symbols 1. Dominant alleles are always capitalized usually by using the first letter of the trait as the symbol 2. The recessive allele is always represented by the small case letter of the symbol for the dominant allele EXAMPLE: homozygous recessive for stem length x heterozygous for stem height Genotypes Phenotype Traits Parents (P.) tt x Tt T = tall stem (dominant allele) Gametes (G) t t (male) T. (female) t = short stem (recessive allele) Itt IT+ Tt By convention the dominant allele is written first F1 = Filial 1 = the probable offsprings of Parents (P1) Phenotypic Ratio = 2 Tall : 2 Short stems or 2 tall stem:2 short stem Genotypic Ratio = 2 Tt : 2 tt. or 1 Tt : 1tt Heterozygous for stem height : Homozygous recessive for stem height Symbol r y C Table 1: Mendel's Traits and Symbols for Pea Plants Traits Dominant Allele Symbol Recessive Allele Seed Shape Round R Wrinkled Seed Color Yellow Y Green Seed Coat Color Colored C White Pod Shape Smooth S Constricted Pod Color Green Yellow Stem Height Tall т Short Flower Position Axial A Terminal 9 a Problems 1. Heterozygous for seed color x Homozygous dominant for seed color (Example). 2. Heterozygous for flower position x Heterozygous for flower position ved Bra ed thes 3. Homozygous recessive for seed shape x Heterozygous for seed she & indic that aey ha of his 4. Homozygous dominant for stem height x Homozygous recessive for stem 6. Heterozygous seed color x Homozygous recessive for seed color 7. Constricted pea pod x Constricted pea pod Table 2 Answers to monohybrid problems Parent Male Female Genotypes Gametes Gametes Phenotypic Ratio Genotypic Ratio 1. _Date trait as 1 ol for the Name Genetics Practice Problems #2 – Writing Alleles Period Directions: Using the data in Table 1. write the enotype that correspond phenotype descriptions “e the genotype that corresponds to the em heig Symbol Round Table 1: Mendel's Traits and Symbols for Pea Plants Traits Dominant Allele Seed Shape I Symbol Recessive Allele Seed Color R Wrinkled Green Seed Coat Color White Pod Shape Constricted Pod Color Green Yellow Stem Height Tall Short Flower Position Axial Terminal Yellow Colored Smooth + oo a Phenotype Genotype Phenotype Genotype 1. Heterozygous for height 16. Constricted pod 2. Homozygous dominant for seed shape 17. Short height 3. Heterozygous colored seed coat 18. Green seed color 4. Homozygous green pod 19. Terminal flowers 5. Homozygous short 20. Pure wrinkled 6. Homozygous tall 21. Hybrid tall 7. Homozygous axial 22. Pure round 8. Homozygous terminal 23. Yellow seed pod 9. Heterozygous flower position 24. Hybrid smooth 10. Heterozygous seed color 25. Pure smooth pod 11. Homozygous smooth pod 26. Hybrid pod color 12. Homozygous constricted pod 27. White seed coat 13. Homozygous recessive for seed coat color 28. Wrinkled seed 14. Heterozygous for pod color 29. Pure colored seed coat 15. Homozygous round seed 30. Hybrid flower position
