Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
STATE UNIVERSITY COLLEGE AT BUFFALO Department of Biology Biology 100 Principles of Biology Spring 2004 Dr. Wadsworth Mid-Term Exam 1a Biomolecules, Membranes and Cells Cover Sheet Name: ____________________________________________________ (Print) Instructions. 1. Print your name in the space designated on this cover sheet. 2. Be sure that your exam has 9 pages including this cover sheet. 3. Read each question carefully and answer in the space provide 4. At the end of the exam there are 6 short answer questions. Answer only 5 of these 6 questions. Answering all six questions may reduce your grade. Under the question you choose not to answer, please write the word "Skip". Failure to write "SKIP" under the one question you choose not to answer will reduce your grade. Multiple Choice Choose the best answer for the question or the best ending for each statement. Write the letter (A-E) which corresponds to the best answer on the line before the question. (2 pts each) _____ 1. The functional group phosphate contains the atom phosphorus at its center. Based on the structure of phosphate, what would be the valence # of phosphorus? A. B. C. D. E. 1 2 3 4 5 _____ 2. Which of the subatomic components of an atom determine which element that atom is? A. B. C. D. E. Valence # Electrons Polar Bonds Protons Neutrons _____3. Which of the following chemical bonds is the strongest? A. B. C. D. E. Hydrogen Bonds Oxygen Bonds Covalent Bonds Hydrophobic Interactions Intermolecular Interactions. _____ 4. If an atom with a neutral electric charge has an atomic number of 45 and an atomic mass of 90, then how many protons would it have? A. B. C. D. E. It would have no protons because it is neutrally charged. It would have 90 protons. It would have 180 protons . It would have 45 protons. It would be radioactive. _____5. Only some hydrogen atoms are capable of forming hydrogen bonds. Which of the following characteristics distinguishes those hydrogen atoms that can form hydrogen bonds from those hydrogen atoms that cannot form hydrogen bonds? A. B. C. D. E. They are ions and have a negative charge which attracts other hydrogen atoms They form covalent bonds with carbon atoms which makes them “sticky” They attract other hydrogen atoms They are covalently linked to other hydrogen atoms They are participating in a polar covalent bond. _____ 6. Carbon forms the backbone of all of the biomolecules within cells. Which of the properties of carbon make it more suitable for forming these backbones when compared to other atoms within cells such as oxygen and hydrogen? A. B. C. D. E. It has an atomic mass of 12 It can form 4 covalent bonds It is an electronegative atom It can form polar bonds with hydrogen It easily loses electrons to form an ion _____7. Which of the following functional groups is hydrophobic? A. Carboxyl Group B. Amino Group C. Keto Group D. Methyl Group E. Phosphate Group _____ 8. Polysaccharides are composed of which of the following subunits? A. B. C. D. E. Amino Acids Fatty Acids Alanines Nucleic Acids Sugars ____ 9. The oil found in olives represents a storage form of energy for the olive seed. What type of biomolecule is olive oil? A. B. C. D. E. Triglyceride Protein Nucleic Acid Phospholipid Chitin _____10. Proteins have which of the following functions? A. B. C. D. E. Structural Hormones Enzymes Transport Molecules All of the above _____ 11. The cell walls that surround plant cells are composed of which of the following biomolecules? A. B. C. D. E. Polysaccharides Proteins Nucleic Acids Carbohydrates Lipids _____ 12. Which of the following best describes the “conserved” region of an amino acid? A. B. C. D. E. A long hydrocarbon chain saturated with hydrogens A sulhydry group linked to a carboxyl group A phosphate group linked to a carbon by a high energy bond. A central carbon linked to a carboxyl and amino group A carbon ring with an oxygen atom within the ring _____ 13. Which of the following best describes the function of triglycerides? A. B. C. D. E. Structural component of cells Storage form of energy Backbone of biological membranes A subunit making up cholesterol A molecule made of 4 interlocking carbon rings _____14. Which of the following is more hydrophobic? A. B. C. D. E. Amino Acids Glucose Starch Polysaccharides Triglycerides _____ 15. In which of the following macromolecules would you expect to find a nitrogenous base? A. B. C. D. E. Cellulose Triglycerides DNA Lipids Protein _____ 16. Which of the following would you not find in a prokaryotic cell? A. B. C. D. E. Cytoplasm Ribosome Protein Mitochondria DNA _____ 17. The endosymbiotic theory states that: A. B. C. D. E. Eukaryotes evolved from prokaryotes Mitochondria arose from free living bacteria Prokaryotes evolved from eukaryotes Rough ER produces symbiotic proteins in the cell Viruses reproduce by growing inside of human cells _____ 18. Which of the following structures are found in both animal and plant cells? A. B. C. D. E. Chloroplast Cell Wall Central Vacuole Stroma Mitochondria _____ 19. Which of the following best describes the function of the golgi in cells. A. B. C. D. E. It inserts proteins into fluid mosaic membranes. It breaks downs sugars to provide the cell energy It synthesizes the phospholipids component of membranes It synthesizes all the proteins in the cell It sorts membranes to different parts of the cell. _____ 20. Which of the following is an example of a prokaryotic cell? A. B. C. D. E. Plant cell Human cell Fungal cell Bacterial cell Animal Cell _____ 21. Unsaturated fatty acids cause membranes to remain fluid at low temperatures. What is the chemical property of these phospholipids that promotes membrane fluidity? A. The double bonds in the hydrocarbon chains causes kinks that prevent the chains from packing tightly together B. The loss of hydrogen associated with unsaturation makes the fatty acids “lighter” so that they don’t congeal in the membrane. C. Unsaturated fatty acids attract more cholesterol than saturated fatty acids. D. Unsaturated fatty acids have long and straight hydrocarbon chains that do not get knotted up so they can move around each other at the lower temperatures. E. Unsaturated fatty acids bind to integral membrane proteins which promote membrane fluidity. _____ 22. Which of the following best describes the results of the activity of the sodium/potassium pump? A. B. C. D. E. It converts chemical energy into electrical energy It pumps glucose from the intestine into the circulatory system It is responsible for osmosis in animal cells It is the classic example of facilitated transport It converts osmosis into simple diffusion _____ 23. Which of the following is true about carrier proteins involved in facilitated transport? A. B. C. D. E. They extend across the bilayer membrane They hydrolize ATP as an energy source They reduce activation energy They lack the specificity of enzymes They are only found in animal cells _____24. Biological membranes are called selectively premeable membranes because: A. B. C. D. E. They are composed of about 50% protein and 50% lipids Charge molecules can not pass through the membrane Active transport requires energy Only some molecules pass through the membrane Active transport requires a carrier protein _____25. Which of the following is least likely to diffuse through a biological membrane? A. B. C. D. E. Oxygen Carbon Dioxide Sodium ions Water the small uncharged molecule methane Short Answer Questions Answer only five of the following six questions in the space below each question. Under the one question you choose not to answer, write the word "SKIP". 26. The structure of the amino acid aspartate is drawn below. Explain why this molecule would or would not be considered amphipathic. 27. Draw the structure of a monounsaturated fatty acid. 28. Draw the structure of a mitochondria and clearly label the two membranes and the spaces separated by those membranes. 29. Describe the subatomic structure associated with a polar covalent bond. 30. Compare and contrast active transport with facilitated transport. 31. How does cholesterol affect the fluidity of biological membranes?