1. What was Mendel's explanation for why some traits seem to skip generations?
  2. One of Mendel’s experiments was a monohybrid cross between plants with wrinkled peas and plants with round peas. Outline a monohybrid cross with these plants. Assuming the round phenotype is dominant, what results do you expect in the F1 and F2 generations?
  3. What is a testcross and why would a scientist use it?
  4. In humansachondroplasia type dwarfism phenotype is dominant. Explain how it possible for two healthy people to have a child with dwarfism. (Hint this involves the source of new genetic variation.)
  5. In Labrador retrievers, black fur is dominant to chocolate fur. What are the possible genotypes of a dog with chocolate fur; what are the possible genotypes of a dog with black fur?
  6. Suppose you got a stray black Labrador retriever at the SPCA whose parents were unknown. Design an experiment to determine the genotype of this dog.
  7. What are the possible results from the experiment you designed in question 6 and what conclusion would you draw from each type of result.
  8. Explain why it is unnecessary to testcross individuals with the recessive phenotype.
  9. Suppose Mendel cross a truebreeding strain of tall pea plants with purple flowers with a strain that was dwarf with white flowers. In the F1 generation all the plants were tall with purple flowers. What phenotypic ration would you expect in the second generation (F2 generation).
  10. Suppose in the experiment outline in question 9, you got a 3:1 ratio of tall purple flowered plants to dwarf white flowered plants. What would you conclude?
  11. The attached earlobe trait is recessive to the detached earlobe trait. A couple both with detached earlobes has a son with attached earlobes. What is the probability the next child will have attached earlobes?
  12. The classic example of partial dominance in plants is in flower color of four o’clocks plants. A mating of red flowered and white flowered four o’clocks produced plants with pink flowers. What would the F1 plants look like if this trait showed codominance?
  13. What phenotypic ration would you expect if you crossed a pink flowered four o-clocks plant with a white flowered four o-clocks plant?
  14. Why is familiar hypercholesterolemia an example of incomplete dominance in humans?
  15. Explain how it be possible for a women with type A blood and a man with type B blood to have a child with type O blood.
  16. Assuming the couple described in question 4 had a second child. What is the likely hood the next child will have type AB blood?
  17. Why is sickle cell anemia described as displaying pleiotrophy?
  18. What protein does the familial hypercholesterolemia gene encode?
  19. Would it be possible for two people with healthy levels of cholesterol to have a child with familial hypercholesterolemia? Explain your answer.
  20. Why can skin color in humans be described as a multifactorial trait?
  21. Albinism in mice (White fur and pink eyes) is a recessive trait. A mouse with grey fur was trapped in the new science building. Explain how a test cross could be used to determine the genotype of this mouse for the albino gene.
  22. Milk productions in cows is an example of a multifactorial trait. A farmer bought the same breed of Jersey milk cows as his neighbor, but always got less milk/cow compared to his neighbor. What might be the multifactorial explanation for his poor milk production?
  23. The blending theory of heredity predicts that human children will have a level of skin pigmentation somewhere in between their mother and father. However, in this polygenic trait children can often have skin pigmentation darker or lighter than their parents. What is the explanation for this phenomena?
  24. Colorblindness is a recessive X linked trait. If a colorblind woman has children with a non-colorblind man what would you expect the children to be colorblind or have normal vision?
  25. In fruit flies a single gene controls leg length. The allele for long legs is dominant to the recessive allele for short legs. This trait is sex linked. Suppose you mated a long legged male fly with a short legged female fly. What ratio of phenotypes would you expect in the offspring?
  26. Czar Nicholas and Czarina Alexandra’s first son, Alexis, had hemophilia. What are the genotypes of the Czar and Czarina?
  27. What were the possible genotypes of Czar Nicholas’s daughter the Grand Duchess Anastasia for the hemophilia gene?
  28. Consider the pedigree below for a rare genetic disease. Is this disease dominant or recessive? Explain your answer.

  1. Using the letter “A” for the dominant allele and the letter “a” for the recessive allele? What would be the genotypes of the two original parents?
  2. How are the four nucleotides that make up DNA similar and how do they differ?
  3. In the 1920’s why did most scientists think that genes were most likely made of protein?
  4. What did Fredrick Griffith demonstrate about the nature of genes?
  5. How would Avery’s results have differed if protein had been the genetic material?
  6. Suppose that Avery treated heat killed smooth bacteria with RNAse and mixed this treated sample with living rough bacteria. When he injected this mixture into the mouse, the mouse died. What did Avery conclude from these results?
  7. What did Rosalind Franklin’s experiment with X-ray diffraction of DNA demonstrate?
  8. What was Watson and Crick’s major contribution to the structure of DNA?
  9. What determines the order of nucleotides linked together by DNA polymerase?
  10. Eukaryotes like humans and pea plants have multiple origins of replication but bacteria like E. coli have a single origin of replication. Explain why eukaryotes need multiple origins of replication and bacteria do not.
  11. What are the two parts of the central dogma of molecular biology?
  12. What would be the sequence of amino acids in the polypeptide encoded by the following mRNA?

GGCGAUCGCCGACAGGUCUCGAAUGGCAUCCGGUACAUCCUAACGGCUGGUGUCGAAACAGUCAAUCGGCU

  1. In animals only about 25% of the genome is transcribed by RNA polymerase. What determines which regions are transcribed and which are not transcribed?
  2. Name a type of RNA that doesn’t include an open reading frame in its sequence.
  3. What triggers transcriptional termination and what happens to the RNA polymerase during transcriptional termination?
  4. What happens during transcriptional initiation?
  5. At the end of translational initiation, what are in the A and P sites of the ribosome?
  6. During translation elongation, what are in the A and P sites immediately after translational translocation?
  7. After which stage of translation would you expect to find a tRNA in the P site without an amino acid attached to it?
  8. Of the three stages of translational elongation, which stage occurs immediately prior to translational termination.
  9. After translational termination, what components are recycled and can reengage in another round of translation.
  10. Explain why a non-sense mutation would be expected to have a bigger effect on phenotype than a mis-sense mutation.
  11. Explain how a base substitution could result in a silent mutation.
  12. Explain why there cannot be a silent mutation in a tryptophan codon.
  13. What physically prevents transcription of the lac operon in the absence of lactose?
  14. Under what environmental conditions would you expect the lac repressor to be bound to the lac operator?
  15. If you had a mutant E. coli cell that lacked the lac repressor, how would expression of the lac operon change?
  16. What is meant by the term “differential gene expression” in humans?
  17. Why would the hemoglobin gene be described as a luxury gene and not a house keeping gene?
  18. Would the eyeless gene best be described as a luxury gene or a housekeeping gene?
  19. What happens if the eyeless gene is absent in fruit flies?
  20. What happens if the eyeless gene is expressed in every cell of a fruitfly?
  21. What gene is responsible for making sure the eyeless gene is only expressed in the head of fruitflies?
  22. What is the SRY gene and where would you find it?
  23. Explain why a mutation in the SRY gene could result in a XY individual having a female phenotype?
  24. What protein does the gene for testicular feminization encode?
  25. What would be the phenotype of an XX individual with a mutation in the gene for testicular feminization?
  26. Contrast the phenotypes of XY individuals with a mutation in the SRY gene and XY individuals with mutations in the testicular feminization gene.
  27. Suppose a mutation in a gene altered the mRNA sequence by changing the single nucleotide circled below from a C to an A.

ACGUUGUAUGCGGUACUCCUGACGA

ACGUUGUAUGCGGUAAUCCUGACGA

What class of mutation would this be (missense, nonsense or silent)?How would this mutation affect the structure of protein encoded by this gene?