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Genetics - Test 1


1. In pea plants, tall is dominant over short. What size pea plants would result when two short plants are crossed?

  A. short plants only
  B. short and tall plants
  C. tall plants only
  D. middle-sized plants


2. A cleft chin in humans is coded by the dominant allele C. A chin without a cleft is coded by the recessive allele c. A man with a cc allele combination for the trait produces a zygote with a woman with a Cc allele combination for the trait. Which allele combinations could occur in the zygote?

  A. Cc or cc
  B. CC or Cc
  C. CC only
  D. Cc only


3. In pea plants, the trait for round seeds is dominant over the trait for wrinkled seeds. If a pure dominant plant with round seeds is crossed with a plant with wrinkled seeds, what can be predicted about the offspring plants?

  A. They will always produce round seeds.
  B. They will only produce wrinkled seeds.
  C. Each offspring plant will have some round and some wrinkled seeds.
  D. Unless the plant with wrinkled seeds was pure recessive, no prediction can be made.


4. One parent has brown eyes (BB) and has offspring with another parent who has blue eyes (bb). What is the probability that one of their children will have blue eyes?

  A. 0%
  B. 25%
  C. 50%
  D. 100%


5. Tall plants are dominant to short plants. What is the outcome if two short plants are crossed?

  A. all tall plants
  B. all short plants
  C. half tall plants, half short plants
  D. 1/4 tall plants, 1/3 short plants


6. Red is dominant to white for flower color in a particular plant. If a red flowered plant (RR) is crossed with a white flowered plant (rr), what color will the offspring be?

  A. 100% pink
  B. 100% red
  C. 50% white, 50% red
  D. 100% white


7. A "widow's peak" hairline in humans is coded by the dominant allele W. A straight hairline is coded by the recessive allele w. A man with a homozygous dominant WW produces a zygote with a woman with a heterozygous dominant Ww for the trait. Which allele combinations could occur in the zygote?

  A. WW or ww
  B. WW or Ww
  C. WW only
  D. Ww only


8. Sickle cell anemia is a condition that affects the shape of a red blood cell. An unaffected individual can be represented with the genotype AA. An affected individual can be represented with the genotype SS. Individuals that are carriers have the genotype AS. Which is the best description of sickle cell anemia?

  A. multiple alleles
  B. incomplete dominance
  C. homozygous recessive
  D. heterozygous dominant


9. A student's mother is heterozygous for attached earlobes, a recessive trait. The student's father is also heterozygous for that trait. What is the percent likelihood that this student has attached earlobes?

  A. 0%
  B. 25%
  C. 50%
  D. 75%


10. In whitetail deer, females seldom grow antlers. Which best explains why male whitetail deer grow antlers but females seldom grow antlers?

  A. Female deer have no need for antlers.
  B. Male deer are older than female deer.
  C. Antler growth is controlled by genes.
  D. Antler growth depends on behavior.






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