Chapter 2 Solved Questions
7.
In some genetically engineered corn plants the dominant allele (BT) produces a protein
that is lethal to certain flying insect pests that eat the corn plants. If the corn plant is heterozygous for BT and the farmer collects self-fertilized corn for next year's crop, what proportion of
those plants would be toxic to insects?
10.
In a cross of AAbb x aaBB, how frequent is an AaBB individual in the F2 offspring? If
you answer this using a Punnett square could you also do it using the product and sum rules?
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11.
If an individual has 7 gene pairs, how many different gametes can be formed if two of
the gene pairs are homozygous and the remaining 5 gene pairs are heterozygous?
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16. True-breeding pea plants that have yellow, wrinkled seeds, yellow pods, and purple flowers were crossed with true-breeding pea plants that have green, smooth seeds, green pods,
and white flowers. The resulting F1 progeny from that cross all have yellow, smooth seeds,
green pods, and purple flowers. If the F1 from the cross above are crossed with true-breeding
yellow, wrinkled seed, yellow pod, purple flower plants, what is the probability of observing an
F2 plant with yellow, smooth seeds, yellow pods, and purple flowers?
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17. A woman whose father was diagnosed with the dominant Huntington Disease (HD) marries
a man whose family has no history of the disease. The woman does not know if she carries
the trait and she is pregnant with the couple's first child. What is the probability that the child
will develop HD?
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Chapter 2 Solved questions
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18. Cystic fibrosis (CF) is a recessive trait that causes a fatal lung disorder, with symptoms beginning in early childhood. A healthy woman whose brother has CF marries a healthy man
who has a sister with CF. What is the probability that their first child will have CF?
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Chapter 2 Solved questions
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20. A man and woman go to see a genetic counselor. They are concerned because they have a
common ancestor. It is their great-grandmother. The man and woman have different greatgrandfathers because she had two husbands. The great-grandmother was known to be heterozygous for the recessive disease cystic fibrosis (CF). The great-grandfathers do not carry
the disease gene. The counselor tells them the probability of their first child having CF is:
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