Mendel and the Gene First Group Dynamic Study Module

1. In Drosophila, the eye color gene is on the X chromosome. The red eyes allele (W) is dominant over the white eyes allele (w). If a red-eyed homozygous female is crossed with a white-eyed male, what is the genotypic ratio of the F2 generation? CORRECTANSWER: 1 1 1 1 2. 3. If a homozygous male for round peas (RR) is crossed with a homozygous female for wrinkled peas (rr), which of the following statements is true? 4. CORRECTANSWER: The F 5. 1 6. 1 generation of this cross will produce one kind of gamete that contains R alleles and another kind that contains r alleles. 6. 7. A model organism is . CORRECTANSWER: an organism that is used to study a scientific question, the results of which have applications to other species 8. 9. Which of the following statements is true about a six-foot-tall man who has children with a five-foot-tall woman? (Assume the children had adequate nutrition during development.) CORRECTANSWER: The height of the offspring will vary in a normal distribution near the average height of the parents. 10. 11. Genetics is a branch of biology focused on CORRECTANSWER: the inheritance of traits . 12. 13. If an individual with type O blood mates with an individual with type AB blood, what are the possible blood phenotypes of their offspring? CORRECTANSWER: A and B 14. 15. If an organism is heterozygous for two linked traits, how many genotypes are possible in the gametes produced from a single germ-line cell if a single crossing over event between the two linked genes occurred during meiosis I? CORRECTANSWER: Four 16. 17. If an organism is heterozygous for two traits that are linked, how many genotypes are possible in the gametes produced from a single germ-line cell? Assume that no crossing over occurs. CORRECTANSWER: Two 18. 19. If an individual is heterozygous for hair color (Hh) and eye color (Ee), which of the following statements is true? CORRECTANSWER: The individual can make gametes that contain HE, He, hE, or he. 20. 21. Which of the following features of peas was an important aspect of Mendel’s work? CORRECTANSWER: The ability to control mating between pea plants 22. 23. Which of the following is true about traits affected by linkage? CORRECTANSWER: The traits are the result of genes that have a physical association on the same chromosome. 24. 25. A mother with blood type AB and a father with blood type O have a baby. At the hospital, a nurse congratulates the father and tells him that the baby has blood type O. What would he think? CORRECTANSWER: "This is not our baby!" 26. 27. A fruit fly has a genotype of AABbCcddEEffGg. Which of these is a possible gamete that it could produce? CORRECTANSWER: ABCdEfG 28. 29. In red wheat plants, the color of the kernels varies in intensity from pale white to dark-red. Three independent genes contribute to pigment production. The dominant A, B, and C alleles contribute equally to pigment production in an additive way. The recessive a, b, and c alleles do not contribute to pigment production. Which of these genotypes would have the darkest red phenotype? CORRECTANSWER: AABbCC 30. 31. Which of the following results from the segregation of chromosomes? CORRECTANSWER: Each gamete formed in an organism will have one copy of each gene. 32. 33. Which of the following statements about an X-linked dominant disease is true? CORRECTANSWER: All female offspring from an unaffected female and an affected male would have the disease. 34. 35. An organism's phenotype is CORRECTANSWER: the traits exhibited by the organism . 36. 37. Biologists refer to the observable traits of an individual, such as the shape of a pea seed or the eye color of a person, as its . CORRECTANSWER: phenotype 38. 39. Mendel was a monk and also the cook at a monastery. In which of the following model organisms did he study the mechanisms of inheritance that ultimately led to the chromosome theory of inheritance? CORRECTANSWER: Garden peas 40. 41. Which of the following statements about pure-breeding plants is true? CORRECTANSWER: The offspring of two plants that are cross-pollinated will be hybrids only if, for one or more traits, one parent plant exhibits the dominant trait and the other exhibit the recessive trait. 42. 43. A woman who is a carrier of an autosomal recessive genetic disease marries a man with the disease. Their only child is a girl without the disease. In a pedigree, you would show the woman as . CORRECTANSWER: a half-filled circle 44. 45. A cross between pure-breeding chicken lines with rose combs and pea combs produces offspring that all have a new phenotype, walnut comb. If two walnut comb chickens are mated, the offspring will have the following phenotypes: walnut comb, rose comb, pea comb, and a new phenotype called singlecomb. Which of the following statements best explains this result? CORRECTANSWER: The alleles of two genes are interacting to produce the different phenotypes. 46. 47. A botanist studying the inheritance of flower color found that when she crossed the offspring of two pure-breeding flower lines, one purple and one white, she got the following F2 generation from planting 60 seeds: 17 plants with purple flowers, 26 plants with lavender flowers, and 15 plants with white flowers. This is an example of CORRECTANSWER: incomplete dominance . 48. 49. What is the frequency of each phenotype in the F 50. 2 51. 2 generation of a cross between two homozygous parent peas with the genotypes RR and rr? CORRECTANSWER: Three round, one wrinkled 52. 53. If an F1 plant with the genotype RrYy self-fertilizes, what is the phenotypic ratio of the F2 generation? Keep in mind that R is the dominant allele for seed shape (round), r is the recessive allele for seed shape (wrinkled), Y is the dominant allele for seed color (yellow), and y is the recessive allele for seed color (green). CORRECTANSWER: Nine round, yellow: three round, green: three wrinkled, yellow: one wrinkled, green 54. 55. In snapdragon plants, T is the dominant allele for plant height (tall), t is the recessive allele for plant height (dwarf), RR flowers are red, rr flowers are white, and Rr flowers exhibit incomplete dominance and are pink. A cross between Ttrr and TtRR results in what proportion of offspring with pink flowers on dwarf plants? CORRECTANSWER: One-quarter 56. 57. The hypothesis suggested that an offspring’s traits are intermediate between the mother’s and father’s traits. CORRECTANSWER: blending inheritance 58. 59. If the first five seeds (offspring) grown from a cross between two heterozygous parent peas with the genotype Rr are all round, what is the probability that the next offspring from these parents will be wrinkled? CORRECTANSWER: 25 percent