USABO Open Exam 2009 Questions And Answers

USABO Open Exam 2009 Questions And Answers Sunflower chromosomes have been isolated and their DNA/NT analyzed. It was found that chromosome 2 has unusually high content of Adenine (40%). How many percent of Guanine is present in chromosome 2? A. 10% B. 20% C. 30% D. 40 % E. 50% - ANS A. 10% Sunflower chromosomes have been isolated and their DNA/NT analyzed. It was found that chromosome 2 has unusually high content of Adenine (40%). Assume that the entire sequence of the chromosome is transcribed. Which of the following is true for the content of Adenine in the transcribed RNA? A. Adenine is 40% of the RNA. B. Adenine is 20% of the RNA. C. Adenine is at least 20% of the RNA. D. Adenine is at least 40% of the RNA. E. The content of Adenine is not possible to determine based on the information provided. - ANS E. The content of Adenine is not possible to determine based on the information provided. Which of the following is a primary organ or structure of the immune system? A. Spleen B. Thymus C. Tonsils D. Lymph nodes E. Appendix - ANS B. Thymus "Hairs" (such as trichomes) on the surface of leaves may limit: A. photosynthesis. B. intake of carbon dioxide. C. evapotranspiration. D. drought adaptations. E. movement of water in the vessels. - ANS C. evapotranspiration.