tailieunhanh - Đề thi INTERNATIONAL BIOLOGY OLYMPIAD lần thứ 20

THEORETICAL TEST: PART A GENERAL INSTRUCTIONS 1. Open the envelope after the start bell rings. 2. A set of questions and an answer sheet are in the envelope. 3. Write your 4-digit student code in every student code box. 4. The questions in Part A have only one correct answer. Mark the correct answer with “X” on the Answer Sheet clearly, as shown below. | ENVELOPE COVER SHEET Student Code __ 20th INTERNATIONAL BIOLOGY OLYMPIAD Tsukuba JAPAN 12th - 19th July 2009 THEORETICAL TEST PART A Time available 120 minutes GENERAL INSTRUCTIONS 1. Open the envelope after the start bell rings. 2. A set of questions and an answer sheet are in the envelope. 3. Write your 4-digit student code in every student code box. 4. The questions in Part A have only one correct answer. Mark the correct answer with X on the Answer Sheet clearly as shown below. No. A B C D E F A0 X 5. Use pencils and erasers. You can use a scale and a calculator provided. 6. Some of the questions may be marked DELETED . DO NOT answer these questions. 7. Stop answering and put down your pencil IMMEDIATELY after the end bell rings. IBO-2009 JAPAN THEORETICAL TEST Part A Student Code 20th INTERNATIONAL BIOLOGY OLYMPIAD Tsukuba JAPAN 12th - 19th July 2009 THEORETICAL TEST PART A Time available 120 minutes GENERAL INSTRUCTIONS 1. Write your 4-digit student code in every student code box. 2. The questions in Part A have only one correct answer. Mark the correct answer with X on the Answer Sheet clearly as shown below. No. A B C D E F A0 X 3. Use pencils and erasers. You can use a ruler and a calculator provided. 4. Some of the questions may be marked DELETED . DO NOT answer these questions. 5. The maximal points of Part A is 81 point each question . 6. Stop answering and put down your pencil IMMEDIATELY after the end bell rings. GOOD LUCK 1 IBO-2009 JAPAN THEORETICAL TEST Part A Cell Biology A1. Which treatment is most effective in breaking as many hydrogen bonds as possible in an aqueous solution pH of 1 mg mL DNA and 10 mg mL protein A. Addition of hydrochloric acid to make the pH . B. Addition of sodium hydroxide solution to make the pH . C. Addition of urea to a concentration of 6 mol L. D. Addition of sodium dodecyl sulfate a detergent to a concentration of 10 mg mL. E. Heating the solution to 121 C. F. Freezing the