Genetics Practice Problems. 1. For each genotype, indicate whether it is heterozygous (HE) or homozygous (HO) AA Bb Cc Dd.

Transcription

1 Name Period Genetics Practice Problems 1. For each genotype, indicate whether it is heterozygous (HE) or homozygous (HO) AA Bb Cc Dd Ee ff GG HH Ii Jj kk Ll Mm nn OO Pp 2. For each of the genotypes below, determine the phenotype. Purple flowers are dominant to white flowers PP Pp pp Brown eyes are dominant to blue eyes BB Bb bb Round seeds are dominant to wrinkled RR Rr rr Bobtails are recessive (long tails dominant) TT Tt tt 3. For each phenotype, list the genotypes. (Remember to use the letter of the dominant trait) Straight hair is dominant to curly. straight straight curly Pointed heads are dominant to round heads. pointed pointed round 4. Set up the square for each of the crosses listed below. The trait being studied is round seeds (dominant) and wrinkled seeds (recessive) Rr x rr What percentage of the offspring will be round? Rr x Rr What percentage of the offspring will be round?

2 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. The offspring from the previous question are crossed. 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 plant is 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?

3 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! Part II: Sex Linked 16. Chromosome pair 23 in males is. Chromosome pair 23 in females is. 17. A male and female cross. What is the probability that they will have a son? 18. In chickens, silver feathers result from a dominant sex-linked gene (X G ), and gold feathers from a recessive gene (X g ). Show the results of a cross between a gold-feathered hen and a silver feathered rooster. Phenotypes: Genotypes: 19. In fruit flies white eyes is a recessive sex-linked trait (X r ). Red eyes is a dominate sex-linked trait (X R ). Diagram a cross between a white-eyed female and a red-eyed male. Phenotypes: Genotypes: 20. A Women how is heterozygous for red-green color blindness marries a man who is not color blind. They have 2 sons and 1 daughter. What is the probability that both of their sons is color blind?

4 PART III: CO-DOMINANCE 21. A man with type AB blood marries a woman with type B blood. Her mother has type O blood. List the expected phenotype & genotype frequencies of their children. 22 The father of a child has type AB blood. The mother has type A. Which blood types can their children NOT have? 23 A woman with type A blood and a man with type B blood could potentially have offspring with what blood types? 24 The mother has type A blood. Her husband has type B blood. Their child has type O blood. The father claims the child can t be his. Is he right? 25 The mother has type B blood. Her husband has type AB blood. Their child has type O blood. The father claims the child can t be his. Is he right?

5 26 The mother has type AB blood. The father has type B blood. His mother has type O blood. What are all the possibilities of blood type for their children? Part III Dihybrid Cross: A dihybrid cross involves a study of inheritance patterns for organisms differing in two traits. Mendel invented the dihybrid cross to determine if different traits of pea plants, such as flower color and seed shape, were inherited independently. We now know that traits are inherited together if they are on the same chromosome. Predict the Results of the following genotype: Father: FfEe Mother: FfEe F = Black Fur f = White Fur E = Black Eyes e = Red Eyes How many offspring will have the exact same genotype as the parents? How many offspring will have Black Fur (F) and Red Eyes (e) A corn Plant RrSs, which produces red starchy grains, is crossed with a plant, rrss, which produces white sweet grains. What number of plants would be expected to be: RrSs Red and sweet grained White and sweet grained rrss

6 PART IV: REVIEW PROTEIN SYNTHESIS PRACTICE Interpreting diagrams is an important skill in learning science. The following diagram illustrates protein synthesis the making of a protein from a gene. Let s interpret the diagram by labeling its parts