Name ____________________________
Ch 9 Homework
1. Cystic fibrosis is a recessive genetic disorder. Ron is homozygous dominant (FF) and Nancy is a carrier
(Ff) of cystic fibrosis. Use a Punnett square to predict the probability that one of their children will have
cysticfibrosis. Include the probabilities for genotype and phenotype of the offspring. Show all work and
box your final answer. (1)
2. Patty is homozygous dominant for freckles (SS), while Charlie is homozygous for no freckles (ss). Draw
a Punnett square predicting the probability if their children will have freckles. Include the probabilities
for genotype and phenotype of the offspring, Show all work and box your final answer. (1)
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3. Imagine that Patty and Charlie’s children (from Q 2) were separated at birth, inadvertently met, fell in
love and had children of their own. Draw a Punnett square predicting the probability if their children will
have freckles. Include the probabilities for genotype and phenotype of the offspring, Show all work and
box your final answer. (1)
4. In humans colorblindness (b) is an example of a sex-linked recessive trait. In this problem, a male with
colorblindness marries a female who is not colorblind but carries the (b) allele. Using a Punnett square,
determine the genotypic and phenotypic probabilities for their potential offspring. Show all work and
box your final answer. (1)
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5. All the offspring of a cross between a black-eyed fly and an orange-eyed fly have black eyes. This
means that the allele for black eyes is ________ the allele for orange eyes. (1)
A) codominant to
B) recessive to
C) more aggressive than
D) dominant to
E) better than
6. Contrast ‘polyegenic inheritance’ and ‘pleiotropy.’ (1)
7. Define genotype and phenotype. Also, include an example where you tell me the genotype and
phenotype of an individual (it can be theoretical). (1)
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8. Explain incomplete dominance and codominance (1).
9. Sex-linked conditions are more common in men than in women because (1)
A) men acquire two copies of the defective gene during fertilization.
B) men need to inherit only one copy of the recessive allele for the condition to be fully expressed.
C) women simply do not develop the disease regardless of their genetic composition.
D) the sex chromosomes are more active in men than in women.
E) the genes associated with the sex-linked conditions are linked to the Y chromosome, which
determines maleness.
10. What are linked and sex-linked genes (1)
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Ch 10 homework
1. Outline DNA replication. Include the jobs of DNA polymerase and ligase during DNA replication,
and the 4 “phases” (1)
2. Explain the difference between transcription and translation. (1)
3.
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Which of the following enzymes catalyzes the elongation of a new DNA strand? (.5)
a. helicase
b. primase
c. ligase
d. single-stranded binding protein
e. DNA polymerase
4. What are the complimentary base pairs of DNA and RNA and what type of a bond holds the base
pairs to its compliment ?(1)
5. What is the job of the ribosome and the tRNA molecule while using mRNA to make a
polypeptide?(1)
6.
Where do transcription and translation occur in prokaryotic cells? (.5)
a. on the plasma membrane
b. in the nucleus
c. in the cytoplasm
d. in chromatophores
e. in the cell wall
7. Multiple origins of replication on the DNA molecules of eukaryotic cells serve to (.5)
a. remove errors in DNA replication.
b. create multiple copies of the DNA molecule at the same time.
c. shorten the time necessary for DNA replication.
d. reduce the number of "bubbles" that occur in the DNA molecule during replication.
e. assure the correct orientation of the two strands in the newly growing double helix.
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8. Explain the process in which amino acids are added make new polypeptides (1)
9. Explain how DNA mutations lead to evolutionary changes (1)
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10. Explain three ways bacteria obtain new genetic material (1)
11. If one strand of DNA is CGGTAC, the corresponding strand would be (.5)
a. GCCTAG.
b. CGGTAC.
c. GCCAUC.
d. TAACGT.
e. GCCATG.
12. Show how new proteins are made, from DNA to RNA to protein (1)
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