Genetics Practice Problems

Genetics Practice Problems - Simple Worksheet 1. For each genotype below, indicate whether it is heterozygous (He) or homozygous (Ho) AA _____ Ee ____ Ii _____ Mm _____ Bb _____ ff ____ Jj _____ nn _____ Cc _____ Gg ____ kk _____ oo _____ DD _____ HH ____ LL _____ Pp _____ 2. For each of the genotypes below determine what phenotypes would be possible. Purple flowers are dominant to white flowers. Brown eyes are dominant to blue eyes PP __________________ BB ________________ Pp __________________ Bb ________________ pp __________________ bb ________________ Round seeds are dominant to wrinkled seeds. Bobtails in cats are recessive. RR __________________ Rr __________________ TT _________________ Tt _________________ tt __________________ rr __________________ 3. For each phenotype below, list the genotypes (remember to use the letter of the dominant trait) Straight hair is dominant to curly. Pointed heads are dominant to round heads. ____ straight _____ pointed ____ straight _____ pointed ____ curly _____ round 4. Set up the Punnet squares for each of the crosses listed below. Round seeds are dominant to wrinkled seeds. Rr x rr What percentage of the offspring will be round? _______________ RR x rr What percentage of the offspring will be round? _______________ RR x Rr What percentage of the offspring will be round? _______________ Rr x Rr What percentage of the offspring will be round? _______________ Practice with Crosses. Show all work! 5. A TT (tall) plant is crossed with a tt (short plant). What percentage of the offspring will be tall? ___________ 6. A Tt plant is crossed with a Tt plant. What percentage of the offspring will be short? ______ 7. A heterozygous round seeded plant (Rr) is crossed with a homozygous round seeded plant (RR). What percentage of the offspring will be homozygous (RR)? __________ 8. A homozygous round seeded plant is crossed with a homozygous wrinkled seeded plant. What are the genotypes of the parents? __________ x __________ What percentage of the offspring will also be homozygous? ___________ 9. In pea plants purple flowers are dominant to white flowers. If two white flowered plants are cross, what percentage of their offspring will be white flowered? ______________ 10. A white flowered plantis crossed with a plant that is heterozygous for the trait. What percentage of the offspring will have purple flowers?___________ 11. Two plants, both heterozygous for the gene that controls flower color are crossed. What percentage of their offspring will have purple flowers? ____________ What percentage will have white flowers? ___________ 12. In guinea pigs, the allele for short hair is dominant. What genotype would a heterozygous short haired guinea pig have? _______ What genotype would a purebreeding short haired guinea pig have? _______ What genotype would a long haired guinea pig have? ________ 13. Show the cross for a pure breeding short haired guinea pig and a long haired guinea pig. What percentage of the offspring will have short hair? __________ 14. Show the cross for two heterozygous guinea pigs. What percentage of the offspring will have short hair? ________ What percentage of the offspring will have long hair? _______ 15. Two short haired guinea pigs are mated several times. Out of 100 offspring, 25 of them have long hair. What are the probable genotypes of the parents? ________ x ___________ Show the cross to prove it!