Review Questions
5. Mendel performed hybridizations by transferring pollen from the _______ of the male plant to the female ova.
- anther
- pistil
- stigma
- seed
6. Which is one of the seven characteristics that Mendel observed in pea plants?
- flower size
- seed texture
- leaf shape
- stem color
7. Imagine you are performing a cross involving seed color in garden pea plants. What F1 offspring would you expect if you cross true-breeding parents with green seeds and yellow seeds? Yellow seed color is dominant over green.
- 100 percent yellow-green seeds
- 100 percent yellow seeds
- 50 percent yellow, 50 percent green seeds
- 25 percent green, 75 percent yellow seeds
8. Consider a cross to investigate the pea pod texture trait, involving constricted or inflated pods. Mendel found that the traits behave according to a dominant/recessive pattern in which inflated pods were dominant. If you performed this cross and obtained 650 inflated-pod plants in the F2 generation, approximately how many constricted-pod plants would you expect to have?
- 600
- 165
- 217
- 468
9. A scientist pollinates a true-breeding pea plant with violet, terminal flowers with pollen from a true-breeding pea plant with white, axial flowers. Which of the following observations would most accurately describe the F2 generation?
- 75% violet flowers; 75% terminal flowers
- 75% white flowers in a terminal position
- 75% violet flowers; 75% axial flowers
- 75% violet flowers in an axial position
10. The observable traits expressed by an organism are described as its ________.
- phenotype
- genotype
- alleles
- zygote
11. A recessive trait will be observed in individuals that are ________ for that trait.
- heterozygous
- homozygous or heterozygous
- homozygous
- diploid
12. If black and white true-breeding mice are mated and the result is all gray offspring, what inheritance pattern would this be indicative of?
- dominance
- codominance
- multiple alleles
- incomplete dominance
13. The ABO blood groups in humans are expressed as the IA, IB, and i alleles. The IA allele encodes the A blood group antigen, IB encodes B, and i encodes O. Both A and B are dominant to O. If a heterozygous blood type A parent (IAi) and a heterozygous blood type B parent (IBi) mate, one quarter of their offspring will have AB blood type (IAIB) in which both antigens are expressed equally. Therefore, ABO blood groups are an example of:
- multiple alleles and incomplete dominance
- codominance and incomplete dominance
- incomplete dominance only
- multiple alleles and codominance
14. In a mating between two individuals that are heterozygous for a recessive lethal allele that is expressed in utero, what genotypic ratio (homozygous dominant:heterozygous:homozygous recessive) would you expect to observe in the offspring?
- 1:2:1
- 3:1:1
- 1:2:0
- 0:2:1
15. If the allele encoding polydactyly (six fingers) is dominant why do most people have five fingers?
- Genetic elements suppress the polydactyl gene.
- Polydactyly