Part I: Short answer (25 points)

Transcription

1 Part I: Short answer (25 points) Part II: / Recently, researchers published a five-year study involving 2,687 subjects with a disorder called sleep apnea. The subjects were between the ages of 45 and 75. TOTAL: / 100 The researchers divided the subjects into two roughly equal groups; one group used a CPAP machine as a sleep apnea remedy, and the other group did not. At the end of the study, the researchers confirmed that the CPAP reduced daytime sleepiness, with corresponding improvements in mood, quality of life, and work productivity. However, they found no impact on the incidence of heart attacks and strokes, or on the rate of hospitalization for heart failure. a. How many dependent variables are mentioned in the description of this experiment? (1 point) b. What is the most important independent variable in this study? (2 points) c. What is the control group? (1 point) d. What is one standardized variable mentioned in this description? (2 points) e. In the space at right, sketch a properly labeled graph showing the results for the incidence of heart attacks (2 points). 2. a. In the space below, draw one neutral oxygen atom (atomic number = 8; mass = 16) and one neutral hydrogen atom (atomic number = 1; mass = 1). For each atom, label protons, neutrons, and electrons as necessary (4 points). Part I: / 25 b. How many covalent bonds do O and H each like to make, and why? (3 points) 3. In the space at right, draw 3 water molecules interacting as they would in liquid water. Label partial charges, one covalent bond, and one hydrogen bond (4 pts). 4. Describe the path of a C atom from the atmosphere, into the starch stored by a plant, into your body, and back out into the atmosphere. In your answer, be sure to name all of the molecules that your C atom is part of, and explain what processes transfer the C atom from one molecule to another (6 pts). 1

2 Part II: 75 points (38 questions; each question is worth 2 points, except the last one) True-false (mark A for true, B for false): 1. Protons and electrons are two types of atoms. 2. The function of photosynthesis is to convert carbohydrates to energy. 3. Enzymes such as ATP are important types of cells in the human body. 4. Plants can t live without water because water participates in both photosynthesis and hydrolysis. Multiple choice / matching: 5. Which of the following items are correctly ranked in order of size, from smallest to largest? a. hydrogen ion (H + ) < electron < nucleus of N atom < nucleus of C atom < CO 2 b. CO 2 < nucleus of N atom < nucleus of C atom < hydrogen ion (H + ) < electron c. nucleus of C atom < nucleus of N atom < CO 2 < hydrogen ion (H + ) < electron d. electron < hydrogen ion (H + ) < nucleus of C atom < nucleus of N atom < CO 2 e. nucleus of N atom < CO 2 < hydrogen ion (H + ) < electron < nucleus of C atom 6. How many of the following six statements are true? o Dehydration synthesis happens in the intestines, then polymers enter the bloodstream and circulate around the body. o Digestive enzymes break down glucose by hydrolysis. o O 2 has to enter the digestive tract for respiration to occur. o Starch has to turn into monosaccharides before digestion can occur. o Respiration converts polysaccharides into monosaccharides. o The enzymes that catalyze hydrolysis reactions have a different shape from the ones that catalyze dehydration synthesis reactions. a. One b. Two c. Three d. Four e. Five 7. Which of the following statements is true? a. A hydrogen bond forms whenever one atom in a molecule is H. b. A proton is happiest if its outermost shell is full. c. A hydrogen bond forms between a positive and a negative ion. d. A hydrogen bond is a type of covalent bond. e. None of the above statements is true. 8. The ph of the contents of your stomach is 3 or lower. Partially digested food then passes to the small intestine, where the ph is about 7.4. The ph difference occurs because the pancreas secretes a substance (bicarbonate) into the small intestine. Based on this information, you can conclude that bicarbonate is: a. an acid b. a base 2

3 9. Once the microscope was invented, people understood for the first time that there are: a. two types of life: plants and animals. b. three domains of life: bacteria, archaea, and eukarya. c. two types of prokaryotic cells: bacteria and archaea. d. single-celled organisms that are neither plants nor animals. e. specialized types of prokaryotic cells, called viruses. 10. The molecule at right is part of: a. ATP d. a carbohydrate b. DNA e. a lipid c. a protein 11. When a female cat produces milk to feed her kittens, which of the organelles in her milk-producing cells is responsible for packaging the fat and proteins into little bubbles (vesicles) to be exported out of the cell? a. flagella d. nucleus b. mitochondria e. Golgi apparatus c. smooth ER 12. According to the tree pasted below: a. fungi are more closely related to animals than they are to plants. b. plants are more closely related to bacteria than they are to animals. c. both a and b are true. d. neither a nor b is true. 13. If an animal cell lacks ribosomes, it will die because it will be unable to: a. digest its enzymes d. make any protein b. store ATP e. all of the above are correct c. build its cell wall The following can be compared in a quantitative sense. Use the choices below to describe the paired statements. a. The first is greater than the second b. The second is greater than the first c. The two are essentially equal 14. Number of mitochondria in a prokaryotic cell number of mitochondria in a eukaryotic cell 15. Number of polar covalent bonds in a hydrophilic substance number of polar covalent bonds in a hydrophobic substance 16. Number of water molecules required to break a polymer consisting of five monomers number of water molecules released when building a polymer consisting of five monomers 3

4 Complete the following table, then answer the questions below. Overall reaction Source of C atoms Source of energy Photosynthesis à Q R Respiration à T U 17. What goes in slots Q and T? a. Q = ATP T = ATP d. Q = O 2 T = CO 2 b. Q = the sun T = ATP e. Q = CO 2 T = glucose c. Q = glucose molecules T = O What goes in slots R and U? a. R = ATP U = ATP d. R = CO 2 U = ATP b. R = the sun U = covalent bonds in glucose e. R = CO 2 U = glucose c. R = glucose molecules U = O What would have to happen to turn a neutral hydrogen atom into a positively charged hydrogen ion (H + )? a. The atom would have to lose a neutron. b. The atom would have to gain a proton. c. The atom would have to lose an electron. d. The atom would have to simultaneously lose a proton and gain an electron. e. Either b or c would work. 20. Which of the following matches a cell type with a dehydration synthesis reaction that it might actually carry out? a. Human cell makes starch out of glucose (to store extra glucose) b. Human cell makes cellulose out of glucose (to build cell membrane) c. Plant cell makes glycogen out of amino acids (to store extra oil) d. Plant cell makes enzymes out of amino acids e. All of the above are dehydration synthesis reactions, but none of them would actually occur in the cells listed. 21. Which molecule illustrated below does not belong with the others? a. V because it is inorganic; all of the others are organic. b. W because all of its covalent bonds are polar; all of the others have nonpolar bonds. c. X because it is organic; all of the others are inorganic. d. Y because its bond is nonpolar; all of the others have polar bonds. e. Z because its two C atoms are sharing 6 electrons with each other; covalent bonds in all other molecules shown here involve sharing only two electrons. V W X Y Z 4

5 22. In the microscopy lab, you measured the thickness of the body coverings of three plants and two animals from different habitats. This measurement is important because the thicker the body covering,. a. the lower the amount of water lost to evaporation from the organism s body. b. the greater the rate at which fluids can enter an organism s body. c. the greater the organism s ability to detect changes in temperature. d. the higher the respiration rate. e. the faster O 2 and CO 2 can enter and leave the body. 23. A seed is about to germinate, so it starts to mobilize the oil (fat) that it has stored to provide energy to the new seedling. If a small portion of the seed contains 3000 oil molecules and enzymes in the cells carry out hydrolysis reactions on all of them, how many fatty acids will have been liberated for the seedling to use? a. 0 b. 100 c. 300 d e Each cell that makes up a plant s leaves has: a. a nucleus d. a, b, and c b. mitochondria e. a and c only c. chloroplasts 25. In class I showed an example of natural selection in bacteria that had been exposed to antibiotics. Which of the following statements about that scenario is/are true? a. The bacteria were genetically variable, even before exposure to the antibiotics. b. The antibiotics were a selective force that killed some (but not all) of the bacteria. c. The bacteria that could survive exposure to the antibiotics had the best chance of surviving and multiplying. d. All of the above statements are true. 26. In the digestion lab, what would have happened if you had forgotten to add bile to the test tubes designated for the digestion of vegetable oil? a. The enzymes would have been denatured, so the oil wouldn t have been digested. b. The purpose of bile is to slow the reaction down, so without bile, the vegetable oil would have digested much too fast for you to be able to detect it. c. The enzymes would have digested themselves instead of the vegetable oil. d. The oil wouldn t have been able to mix with the watery solution containing the enzymes, so the oil wouldn t have been digested. 27. A community of people is a small subset of the world s humans, sharing a neighborhood or a town. In ecology, however, a community is: a. a small part of an ecosystem, surrounded by a defined border. b. a small part of a population, surrounded by a defined border. c. multiple species that interact with each other. d. multiple individuals of the same species that interact with each other. 28. Your heart and brain are organs, which have specific functions and are components of the organ systems that help keep you alive. Your cells contain organelles, which are: a. structures that have specific functions and are surrounded by membranes b. molecules that form the interiors of prokaryotic cells c. smaller than molecules, yet they have the same functions as the heart and brain d. a and c are correct e. a, b, and c are correct 5

6 29. As a seed prepares to germinate, it absorbs water, which triggers the production of an enzyme that carries out the hydrolysis of starch. Why does the germinating seed need this enzyme? a. To allow cells to absorb C atoms across their membranes, so they can convert them to ATP. b. To allow the seedling s cells to build up the monosaccharides into proteins. c. To generate CO 2, which the cells need to break down the starch. d. To generate O 2, which the cells need to break down the starch. e. To generate glucose, which the seedling s cells need to make ATP. 30. Which of the molecules at right is a polysaccharide? a. X b. Y c. Z 31. Which of the molecules at right is most similar to ATP? a. X b. Y c. Z X 32. Molecule Y is part of a(n): a. saturated fat b. unsaturated fat c. hydrophilic amino acid d. hydrophobic amino acid Y 33. Which of the molecules at right would be most happiest among the tails of the phospholipids that make up a cell membrane? a. X b. Y c. Z Z 34. You want to cool down on a hot day, and your friend suggests you fill a plastic bottle with water and put it in the freezer. You say that the water bottle should only be half full when you put it in the freezer. Why are you right? a. Water molecules collapse against each other as they freeze, increasing the density of the water. If the bottle is full when you put it in the freezer, the freezing process will create a dangerous vacuum. b. Water molecules move apart from one another as they freeze, reducing the density of the water. If the bottle is full when you put it in the freezer, the water will expand and break the bottle. c. Water molecules break up into individual O and H atoms as they freeze. This process releases heat. If the bottle is too full, the water inside could actually boil. d. Water molecules form covalent bonds with one another as they freeze. This process requires energy. If the bottle is too full, the bonds will require too many dehydration synthesis reactions to pull them apart. 35. The element phosphorus (P) has many isotopes, with mass numbers ranging from 24 to 46. If P s atomic number is 15, this means that a given P atom might have anywhere from 9 to 31. a. covalent bonds d. protons b. hydrogen bonds e. neutrons c. electrons 6

7 36. The nutrition labels at right compare two beverages: chocolate milk and Coca cola. The serving sizes are equal (i.e., 1 cup = 8 oz). Which one is the healthier choice, and why? a. Coca cola because it has the fewest calories per cup. b. Chocolate milk because it has the most saturated fat per cup. c. Coca cola because it has the most sugar per cup. d. Chocolate milk because it is the only one that contains protein, vitamins, and minerals. Chocolate milk Coca Cola 37. If the tree at right represents all of life s evolutionary history, what three names should go across the tree s tips (from left to right)? a. Bacteria, Plants, Animals b. Bacteria, Archaea, Eukarya c. Protista, Animals, Plants d. Domain, kingdom, phylum e. Family, genus, species 38. Which test form do you have? (1 point) a. Form 1 (green) b. Form 2 (pink) 7