Name: Date: Genetics Exam Review Questions Multiple Choice: Select the best answer to complete each statement. 1. Mendel crossed pea plants with greens seeds (yy) with plants with yellow seeds (YY). The offspring were A. 100% green B. 50% yellow C. 100% yellow D. 25% green 2. If the F 1 plants from question #1 were crossed with each other, what percentage of the offspring would be green? A. 50% B. 0% C. 100% D. 25% 3. Organisms with the genotypes Bb and BB have the same phenotype because A. B is dominant over b B. genes separate independently C. genes assort independently D. all of these 4. In pea plants, purple flowers are dominant over white flowers. If two heterozygous purple-flowered plants are crossed, the resulting ratio of phenotypes in the F 1 generation is A. 1 : 1 B. 3 : 1 C. 1 : 2 : 1 D. none of these 5. Four-o -clocks exhibit incomplete dominance for flower color. If two heterozygous pink (RW) plants are crossed, the probable ratio of genotypes in the offspring is A. 3 RW : 1 WW B. 1 RR : 2 RW : 1 WW C. 1 RR : 1 RW : 1 WW D. 1 RR : 1 WW 6. Roan cattle have coats that are a mixture of both red and white hair. What pattern of inheritance does cattle coat color follow? A. Incomplete dominance B. Codominance C. Multiple alleles D. Polygenic inheritance
7. Which of the following traits is an example of a multiple allele inheritance pattern? A. Blood type B. Rabbit fur color C. Both (a) and (b) D. None of the above 8. Which of the following human traits are not governed by multiple genes (i.e., polygenic inheritance)? A. blood type B. eye color C. skin color D. height 9. Turner s syndrome and Klinefelter s syndrome result from A. oxygen deprivation B. old age C. nondisjunction of sex chromosomes D. a point mutation 10. The photographic representation of an individual s chromosomes is called a A. fetal image B. melanin portrait C. pedigree D. karyotype Karyotypes: Two different karyotypes are displayed below. For each one, decide if they are from a genetically normal person or that of one with a chromosomal disorder. Support your answer by providing each karyotype and phenotype. 2
Matching: Match the description on the left with the term on the right. 11. heterozygous individual display traits that are a blend of the two alleles for a gene 12. alleles separate from each other so that each gamete only carries one gene copy 13. used to calculate the probable ratios of genotypes 14. the chromosomes used to determine an individual s sex 15. the number of chromosomes in a human gamete 16. the number of chromosomes in a human body cell A. Down s syndrome B. autosomes C. Punnett square D. 23 E. nondisjunction F. polygenic inheritance G. incomplete dominance H. segregation I. sex chromosomes J. 46 17. failure of chromosomes to separate during gamete formation 18. paired chromosomes; do not determine sex 19. nondisjunction of the 21 st chromosome 20. traits governed by more than one set of genes 3
Completion: Use your notes to write the correct vocabulary word in each sentence. (No word bank given use your resources.) 21. is the likelihood that something will happen. 22. If a pea plant has the Tt, the plant will be tall. 23. If a rabbit has the alleles BB for the gene for fur color, the rabbit is for that trait. 24. When neither allele is dominant over the other, and both phenotypes are fully expressed in a heterozygous individual, the alleles are said to be. 25. In, both alleles of a gene are expressed and the heterozygous individual is a blend of the phenotypes of both alleles. 26. In, several genes control the phenotype. 27. Which kind of phenotype dominant or recessive can have more than one genotype? Give an example. Short Answers: For the questions given below, make sure when you write out your Punnett square to analyze it! You must answer what the questions are asking for or you will not get full credit. When in doubt, write both the genotype and phenotype. 28. Use the information in the table to answer the questions below: Individual Kathy s father Kathy s mother Kathy Kathy s brother Hair Texture straight curly wavy wavy a. If S is the allele for straight hair and C is the allele for curly hair, then what are the genotypes of each individual in Kathy s family? Explain your answer using Punnett squares. 4
b. What pattern of inheritance is this? How do you know? c. Kathy has the possibility of marrying three different men and they all have different hair textures (straight, wavy, and curly). For each man, predict what type of hair texture their children might have if he and Kathy started a family. Explain your answer using Punnett squares. (You need to make 3 Punnett squares here) a. Straight hair b. Curly hair c. Wavy hair 29. Two pea plants with smooth seed pods are crossed. Some of the offspring have wrinkled seeds. What can you infer about the genotypes of both parents? Show your work. 5
30. In guinea pigs, a black coat is dominant over a white coat. Can two white-coated parents produce an offspring with a black coat? Why or why not? 31. A woman having blood type A marries a man having blood type B. They have five children. Two sons have blood type O. One daughter has blood type AB; another daughter, type A; and a third, type B. What are the genotypes of the parents? Show your work with a Punnett square. 6
32. In garden pea plants, the tall allele (T) is dominant to the short allele (t), and the round seed allele (R) is dominant to the wrinkled seed allele (r). Which of the following crosses could produce short pea plants with wrinkled seeds? SHOW YOUR WORK IN THE SPACE BELOW. A. TtRr TTRR B. TTRr TTRr C. TtRr Ttrr D. TtRR ttrr 7
33. In fruit flies, the gene for eye color is located on the X chromosome, and the red eye allele (R) is dominant to the white eye allele (r). A female with genotype X R X r is mated with a male fly with genotype X r Y. Which of the following statements best describes the expected outcome of the cross? YOU MUST SHOW YOUR WORK WITH A PUNNETT SQUARE! A. The chance of an offspring having red eyes is 75%. B. The chance of an offspring having white eyes is 50%. C. The chance that a male offspring will have white eyes is 0%. D. The chance that a female offspring will have red eyes is 100%. 34. Earlobes may be free or attached. The type of earlobe a person has is genetically determined. The allele for free earlobs (E) is dominant, while the allele for attached earlobes (e) is recessive. The inheritance of the earlobe trait can be traced over several generations using a family tree called a pedigree. A pedigree for the earlobe trait is shown below. 1 2 Key female with free earlobes 3 4 5 6 7 male with free earlobes female with attached earlobes male with attached earlobes 8 9 10 11 12 13 14 #34 continued on the next page 8
#34 continued please refer to the pedigree on the previous page. I. Female #10 is heterozygous for the earlobe trait. Suppose she has five children with a male who is also heterozygous for the earlobe trait. Which of the following describes the most likely phenotypes of the five children? a. All of the children have free earlobes. b. All of the children have attached earlobes. c. Some of the children have free earlobes and some have attached earlobes. d. The female children all have free earlobes and the male children all have attached earlobes. II. If female #3 and male #4 were to have another child, what would be the probability of that child having attached earlobes? a. 25% b. 50% c. 75% d. 100% III. If female #11 has a child with a male who has attached earlobes, which of the following genotypes is possible for the child? a. ee only b. Ee only c. EE or Ee d. EE or ee 9