Virginia State Science Olympiad Regional Tournament

Transcription

1 Stone MS 2013 Mar 16 Virginia State Science Olympiad Regional Tournament 2013 Division B Heredity You may write your name on this sheet before the event examination has begun. Two (2) non-programmable non-graphing calculators, one (1) standard-size (8.5 x11 ) double-sided sheet (not two one-side sheets) of paper containing any information, and writing implements may be used. Any other electronic devices are not allowed for this event; please consult the proctor about a safe location to store these devices for the duration of the event if you happen to carry one; any team caught with an electronic device during the event will be immediately disqualified. Tiebreakers will be tallied according to specified questions and will be used in the order from the front to back; tiebreakers will only be used to break ties and do not count towards your overall score. Student Names: School: Team #:

2 PART A Molecular Genetics! 1. Which of the above karyotypes represents a normal human female? [1pt] a. A b. B c. C d. D e. E f. F 2. Which of the above karyotypes represents a normal human male? [1pt] a. A b. B c. C d. D e. E f. F 3. Which of the above karyotypes represents a person with two (2) chromosomal aneuploidies? [1pt] a. A b. B c. C d. D e. E f. F 4. Which of the above karyotypes represent individuals with Down s syndrome? [1pt] a. A&B d. E&F b. B&D e. None of the above c. B&E 5. Most chromosomal aneuploidies are caused by nondisjunction during meiosis. What is the precise definition of nondisjunction? [2pt] 6. Which of the following chromosomes is most likely to undergo nondisjunction? [1pt] a. 9 d. X b. 18 e. Y c Points:

3 7. Which of the following best demonstrates the central dogma of molecular biology? [1pt] a. DNA RNA protein d. RNA protein DNA b. DNA protein RNA e. protein RNA DNA c. RNA DNA protein 8. Which of the following best describes how DNA and RNA molecules are different? [1pt] a. DNA contain uracil residues, while RNA contain thymine residues. b. Both molecules contain a sugar-phosphate backbone. c. DNA is generally double-stranded while RNA is generally single-stranded. d. DNA is read in a 5 to 3 direction, while RNA is read in a 3 to 5 direction. e. None of the above show accurate differences between DNA and RNA molecules. 9. Which of the following terms best describes the method of replication in DNA? [1pt] a. Conservative d. Anti-discontinuous b. Semi-conservative e. Magic c. Discontinuous The following questions refer to the diagram to the right: 10. Which letters (all) represent interphase? [2pt] 11. Which letter represents the phase where DNA synthesis usually occurs? [1pt] 12. Which letter represents the phase where cell division actively occurs? [1pt] 13. Which of the following statements best illustrates the difference between mitosis and meiosis? [1pt] a. Mitosis results in four haploid daughter cells, while meiosis results in two diploid daughter cells. b. DNA synthesis only occurs once before either mitosis or meiosis. c. During anaphase I, homologous pairs of chromatids are separated; during regular anaphase, homologous pairs of chromosomes are separated. d. Recombination occurs during both mitosis and meiosis. e. None of the above show accurate differences between mitosis and meiosis. 2

4 PART B Attack of the Peas! You ve discovered a new species of pea, with a trait for flower color where allele A (red) is dominant to allele a (white). Q14-16 refer to the first Punnett square, while Q17-20 refer to the second Punnett square. \ Parent (P) cross 14. Complete the sample parent cross to the right between truebred red and truebred white flowers. [3pt] 15. What proportion of peas resulting from the crossing in question 14 is expected to be a hybrid plant? [1pt] d. 75% b. 25% e. 100% c. 50% 16. What is the expected color of the hybrid flowers if the trait is completely incompletely codominant? [2pt] 17. Complete a sample cross between two of the hybrids from the parent (P) cross to the right. [3pt] 18. Which of the following best shows the expected ratio of genotypes resulting from the cross in question 17? [1pt] a. 50% AA; 50% Aa; 50% aa b. 100% AA; 0% Aa; 0% aa c. 0% AA; 100% Aa; 0% aa d. 0% AA; 0% Aa; 100% aa e. 25% AA; 50% Aa; 25% aa First Filial (F1) cross \ 19. What is the expected ratio of phenotypes from Q17 if the flower color trait is (include the phenotype!) completely incompletely co 20. After the F1 cross, what is the relative proportion of alleles ( A and a ) present in the F2 pea population (the alleles present in the progeny)? [1pt] A; 100% a d. 75% A; 25% a b. 25% A; 75% a e. 0% A; 100% a c. 50% A; 50% a 3 Points:

5 It is discovered sometime later that a second gene controls the pea plants appetite for blood (from which the red coloration is surprisingly derived). While preparing to arm yourselves with herbicides, you decide to check out the genetics of the trait, where the allele B (bloodthirsty) is completely dominant to allele b (not-bloodthirsty). 21. Assuming you start with only dihybrid plants, complete the Punnett square to the right. [4pt] 22. What is the probability that any progeny from the cross in question 21 will be AaBb? [1pt] AaBb d. 75% AaBb b. 25% AaBb e. 100% AaBb c. 50% AaBb \ Dihybrid Cross 23. Assuming that flower color is completely dominant, what is the approximate probability that a red flowered pea plant will also be not-bloodthirsty? [1pt] d. 33% b. 19% e. 50% c. 25% 24. What is the approximate probability that a white flowered pea plant will also be bloodthirsty? [1pt] d. 75% b. 19% e. 94% c. 56% 25. Assuming that flower color is not completely dominant (i.e. either incomplete or codominant), what is the approximate probability that any pea plant will be neither red nor bloodthirsty? [1pt] b. 6% c. 19% d. 44% e. 56% 26. By some fortune, you have discovered that another trait color of pea pods ( G is dominant over g ) is actually linked to the bloodthirstiness trait. How might linkage affect the prediction of progeny in a Punnett square? [2pt] TIE-BREAKER In the space below, draw out a Punnett square showing the crossing between dihybrid BbGg pea plants, assuming that the dominant alleles for each trait are linked. 4 Points:

6 PART C - The Royal Disease Hemophilia is a disorder that affected many of the ruling families of Europe during the 19 th and 20 th centuries, thanks largely to the legacy of inter-royal marriages involving children of Queen Victoria. The following pedigree follows the descendants of Queen Victoria: 27. The first daughter of Queen Victoria Empress Frederick (born Victoria Adelaide) of Prussia (B) wedded the Kaiser Frederick III and was the mother to Kaiser Wilhelm II of Prussia (G). As far as we are aware, none of her children suffered from hemophilia (as shown in the pedigree). Based upon this information, what is the probable genotype of the Empress Frederick (B)? [2pt] 28. Tsarina Alexandra (H) was the daughter of Queen Victoria s second daughter Alice (D). The first son of Tsarina Alexandra was born a hemophiliac. Based upon this information, determine the genotype of Alice (D). [2pt] 5 Points:

7 29. Leopold (E) was the only son of Victoria who was actually hemophiliac. Despite his condition, he managed to live until the age of thirty and had two children Alice, Countess of Althona (J) and Charles Edward (I). Explain briefly why the children of Charles Edward (I) never suffered from hemophilia, while Alice s (J) only son was a hemophiliac. [3pt] 30. The final daughter of Queen Victoria was Princess Beatrice (F), whose daughter Victoria Eugenie (K) became consort to Alfonso XIII of Spain. Of her four sons, only two had hemophilia while the other two were normal, including the Infante Juan, Count of Barcelona and father to the current king of Spain. Explain briefly why half of Victoria Eugenie s sons were hemophiliac. [3pt] 31. Based upon this information, what can you determine about the inheritance pattern of hemophilia? [2pt] 32. The present Queen Elizabeth II is the great-granddaughter of Edward VII (C). Her husband is the great-grandson of Princess Alice (D). Based upon this information, what is the probability that Queen Elizabeth s son Prince Charles could have inherited hemophilia [which he does not have, btw]? Explain why briefly. (3pt) 6 Points: