Name: Science 103 (Spring 2006) Integrated Science: Practice for Exam 1 Do this exam AFTER studying and under exam conditions. Make sure you have attempted all questions before attending the review session. Use your quizzes to study also. MULTIPLE CHOICE: 1. Which of the following will not complete the statement below? Only certain bases of DNA can pair because: (A) the helix is a certain width. (B) of complementary hydrogen bonding. (C) purines can only pair with pyrimidines. (D) a nitrogenous base can only pair with a base that is the same size. (E) None of the above - all are true. 2. Amino acids can be defined as: (A) Molecules that contain carbon, hydrogen, and oxygen bonded together to form monosaccharides. (B) Molecules that are insoluble in water but soluble in oil. (C) The building blocks of proteins. (D) Polymers of nucleic acids. (E) None of the above. 3. Fill in the blank. The order of the ______________ of DNA determines the genetic code. (A) sugar-phosphate subunits (B) nitrogenous bases. (C) amino acids (D) pentose sugars (E) phosphate groups 4. Fats are composed of: (A) fatty acids and glycerol. (B) phospholipids and glycerol. (C) fatty acids and phosphate. (D) four connected rings with an attached functional group. (E) amino acids and glycerol. The following statement is for questions 5 and 6. Fill in the blanks: Starch is the storage ____5____ of ____6____. 5. (A) (B) (C) (D) (E) monosaccharide disaccharide lipid nucleic acid polysaccharide 6. (A) (B) (C) (D) (E) plants animals fungi bacteria protists 1 7. Fill in the blank. A nucleic acid is composed of _____________ subunits. (A) amino acid (B) monosaccharide (C) nucleotide (D) nitrogenous base (E) fatty acid 8. The most important form of bond for synthesizing biological molecules is the: (A) ionic bond. (B) covalent bond. (C) hydrogen bond. (D) B and C. (E) all of the above. The following statement is for questions 9 and 10. Fill in the blanks: Polymers are broken down into monomers by ___9___. This breaks the ___10___. 9. (A) (B) (C) (D) (E) addition of water removal of water transfer of an electron addition of monomers addition of oxygen atoms 10. (A) (B) (C) (D) (E) hydrogen bonds ionic bonds sulfhydryl bonds covalent bonds double helix bonds 11. The unique characteristics of each amino acid are due to the physical and chemical properties of the: (A) functional group (“R”). (B) carboxyl group. (C) amino group. (D) glycerol group. (E) hydrocarbon chain. 12. What property of cell membranes prevents them from dissolving in water? (A) The polar heads of the phospholipids. (B) Hydrogen bonding between the phosphate group of the phospholipids and water. (C) The hydrophobicity of the hydrocarbon tails of the phospholipids. (D) The double carbon bonds in the unsaturated hydrocarbon tails of the phospholipids. (E) None of the above. 13. Secondary structure of a protein is the result of: (A) the sequence of amino acids. (B) interactions between the functional groups of the amino acids. (C) the arrangement of the polypeptide chains. (D) denaturation. (E) hydrogen bonding along the polypeptide backbone. 14. The environment of a protein is changed so that the protein has been denatured. What has happened to the protein? (A) It has unfolded. (B) Its shape has changed. (C) It is unable to perform its function. (D) All of the above. (E) None of the above. 2 15. Which of the following is found in BOTH prokaryotes and eukaryotes? (A) Nucleus (B) Membrane-bound organelles (C) Plasma membrane (D) A and B (E) All of the above 16. The part(s) of a phospholipid molecule found on the extracellular surface is/are the: (A) 4 connected rings. (B) nitrogenous bases. (C) nonpolar head. (D) nonpolar tail. (E) polar head. 17. Eukaryotic cells are approximately (A) 5-20 nm (B) 5-20 µm (C) 1 cm (D) 1-10 µm (E) None of the above. 18. The following statement describes ___________. This molecule, which is important for membrane fluidity, has a carbon skeleton of 4 connected rings with different attached functional groups. (A) phospholipid (B) chlorophyll (C) cholesterol (D) starch (E) glucose 19. Watson and Crick determined the structure of DNA in: (A) 1665. (B) 1928. (C) 1944. (D) 1953. (E) 1972. 20. Examples of purines are: (A) adenine and guanine. (B) adenine and cytosine. (C) cytosine ane thymine. (D) cytosine and guanine. (E) none of the above. 21. Chargaff’s rule states that: (A) A=T and C=G. (B) A=C and T=G. (C) A and B. (D) mRNA is copied from DNA. (E) polypeptide chains are translated from the mRNA message. in size. 3 22. Chargaff’s rule: (A) plus other evidence allowed the structure of DNA to be elucidated. (B) suggests a molecule with a constant thickness. (C) suggests a molecule with a regular structure. (D) all of the above. (E) none of the above. 23. RNA contains the same bases as DNA except: (A) adenine. (B) cytosine. (C) guanine. (D) thymine. (E) uracil. 24. Water molecules cross the plasma membrane by: (A) active transport. (B) endoctytosis. (C) exocytosis. (D) osmosis. (E) B and C. 25. The removal of waste products from a cell is an example of: (A) osmosis. (B) endocytosis. (C) exocytosis. (D) active transport. (E) lysis. 26. Which of the following types of transport require an input of energy? (A) Ion channels (B) Facilitated diffusion (C) Osmosis (D) Active transport (E) None of the above. (Multiple choice = 26 points) The rest of the answers go on the exam. 27. (a) Using the accepted diagrammatic representation for phospholipids, draw how they orient themselves in water. 4 (b) Explain why this happens. (4 points) 28. Read the following and write up in the format of the scientific method (include a question, hypotheses, predictions, controlled experiment, and possible conclusions (based on what you might observe)). The drawing below shows an osmometer, which is an instrument used to measure osmotic pressure. Pure water is separated from a sugar solution by a membrane that is permeable to water, but not the sugar molecules. Osmotic pressure can be measured by the movement of the piston. 5