SSSS FORENSICS TEST ANSWER KEY, Schemes and Mind Maps of Forensics

Download SSSS FORENSICS TEST ANSWER KEY and more Schemes and Mind Maps Forensics in PDF only on Docsity! SSSS FORENSICS TEST ANSWER KEY KSSOISLIT Score Calculation Powders: (points earned ______ ÷44) x 20 = ______ + Polymers: (points earned ______ ÷49) x 20 = ______ + Chromatography: (points earned ______ ÷14) x 15 = ______ + Entomology + Blood + DNA + Glass + Fingerprints: (points earned ______ ÷95) x 15 = ______ + Analysis: (points earned ______ ÷113) x 30 = ______ = Score (scaled percentage) = ______ % Crime Scene As the top forensic scientist in the United States, you are often tasked with solving a wide variety of cases. You’ve recently been contacted by a new client looking to hire you to use your forensics skill to investigate an unusualcase. Here’s what the client wrote to you: Hello, I’m writing to ask for your help in investigating a recent tragic event. My beloved white-headed capuchin monkey, Marcel, has been stolen. A few months ago, I placed him under the care of the San Diego Zoo as I no longer had the capacity to care for him myself. However, when I went to visit him a few days ago, he was missing! When I confronted the zoo officials, they said they had reviewed the security footage around the time they believed Marcel was taken and saw five individuals near his zoo exhibit, though there wasn’t any footage of the specific entry point into Marcel’s exhibit (the crime scene). These five individuals happened to include all of my closest friends and my sister. I don’t know why any of them would do such thing, so I’m trusting you to find out who stole my monkey. Please help me find my dear Marcel. Ross Geller The zoo has closed their monkey exhibit and granted you access to the scene, where you have begun your investigation. You’ve collected the following evidence from the crime scene: • Powders: answers to questions #1-8 and #14-16 • Polymers: answers to questions #22-28, #37-38, and #40-41 • Mass spectroscopy: mass spectrograph of #48 shows a substance found at crime scene • Blood: answers to questions #52-53 • DNA: crime scene DNA is shown in #69 • Fingerprints: the complete set of fingerprints in #78 In addition to collecting this physical evidence, you have interviewed each of the suspects and taken blood, DNA, and fingerprint samples from them, which you have recorded below. Ross and Marcel are depending on your forensics skills to solve this crime, so don’t let them down! Suspects Monica Geller: Monica is Ross’s sister. She has always been jealous of Ross because their parents have always favored him and is also extremely competitive with everyone, including Ross. She is a professional chef and likes to cook, bake, grill, etc. at home for her friends. She is also extremely organized. Monica has recently taken on the hobby of indoor gardening. Blood Type O+ Henry System Primary Classification 25/18 DNA 13. Draw a molecule of sucrose. (4 points) Questions 14-16 give the common uses of different powders. Identify the powder and its chemical formula. (2 points each) 14. Used in crafts, casting, and cement Calcium sulfate, CaSO4 15. Used in gardening; as a laxative; to control seizures, asthma, and atrial fibrillation; and in baths Magnesium sulfate, MgSO4 16. Used mainly as a treatment for bipolar disorder Lithium chloride, LiCl 17. What are the components of Benedict’s Solution? (2 points) 0.5 points per component listed Copper sulfate, sodium carbonate, sodium citrate, water 18. If an aqueous solution has a pOH of 9.2, what is its hydrogen ion concentration? (2 points) [H+] = 10-4.8 Polymers (worth 20% of score) Three fibers were burned. Based of their description, label each as Animal, Vegetable, or Synthetic. (1 point each) 19. Melted and shriveled Synthetic 20. Shriveled only Animal 21. Neither shriveled nor melted Vegetable Five more fibers were burned (questions 22-26). Write the name of the fiber that is most likely being described. (1 point each) 22. Smells of burning hair or feathers; burns easily Wool 23. Smells of celery; burns slowly; drips beads with white smoke Nylon 24. Smells of burning paper; burns quickly; leaves whitish ash Cotton 25. Smells of burning hair or feathers; slow to catch fire Silk 26. Smells of burning paper; burns slowly Linen 27. Which of the plastics specified in the Forensics rules has the has resin identification code #1? (1 point) PETE 28. Which of the plastics specified in the Forensics rules has the has resin identification code #3? (1 point) PVC What do the following plastics stand for? Draw the monomer for each. (2 points per question) 1 point for name, 1 point for monomer 29. PETE _________Polyethylene terephthalate__________ Monomer: 30. HDPE __________High density polyethylene___________ Monomer: 31. LDPE __________Low density polyethylene____________ Monomer: 32. PP __________Polypropylene_____________________ Monomer: 33. PVC __________Polyvinyl chloride___________________ Monomer: 34. PMMA __________Polymethyl methacrylate____________ Monomer: 35. PS __________Polystyrene_______________________ Monomer: 36. PC __________Polycarbonate_____________________ Monomer: Questions 37 and 38 give the float test results of different polymers. Identify the polymer in each question. (1 point each) 37. Floats in water, sinks in isopropyl alcohol HDPE 38. Sinks in water, floats in sat. NaCl, sinks in 10% NaCl, sinks in 25% NaCl PC 39. Which of the plastics from questions 29-36 are thermoplastics and which are thermoset plastics? (2 points) 1 point for stating all thermoplastics, 1 point for stating “none” or leaving blank thermosets Thermoplastics______ PS, PP, PVC, LDPE, HDPE, PC, PMMA, PETE _____________________ Thermoset plastics______none___________________________________________________ 40. The hair to the right is from which animal? (1 point) Squirrel 41. The hair to the right is from which animal? (1 point) Bat 42. Draw a simple cross-sectional diagram of hair, labeling the three main layers. (4 points) 1 point per labeled layer, 1 point for drawing an accurate cross-sectional image 43. Name and describe the 4 stages of hair growth. (4 points) 1 point per stage plus description Anagen-hair is actively growing Telogen-hair is transitioning to resting Catagen-hair is resting Exogen-hair is shed 53. What is the least common blood type in humans (include Rh factor)? (1 point) AB- 54. What percentages of the population have those blood types, in the order of most common then least common? (2 points) 1 point per correct value Accept anything between 35 to 40% and 0.5 to 1%, respectively 55. Anti-A is added to a blood sample, which reacts with clumping. Anti-Rh is added to a different sample of the same blood, which does nothing. The hematologist testing these samples is careless, so he forgot to test the blood with anti-B. What are all the possible blood types indicated from these tests? (1 point) 0.5 points per blood type A- and AB- 56. What is the name of the clumping reaction mentioned in Question 55? (1 point) agglutination 57. What blood type is a universal donor? A universal recipient? (2 points) 1 point each O- and AB+, respectively Questions 58-59 refer to the diagram below. The blood spatter pictured above (with its dimensions and orientation labeled) was found at a crime scene. 58. What is the angle of impact of the blood spatter (calculate to the nearest tenth of a degree)? (3 points, 2 for correct answer, 1 for calculations) 16.6° Calculations: θ=arcsin (W/L) θ=arcsin (4/14) θ=16.6 59. Draw an arrow in the direction the blood spatter was travelling on the diagram above. (1 point) Arrow should be drawn from north to south on diagram A B C 60. The slides above show (in random order) microscopic images of blood from a human, a bird, and a reptile. What type of blood does each sample show? (3 points) 1 point each A __________Bird___________B ___________Human__________C __________Reptile___________ 61. What feature of human blood cells is unique from these other blood samples? (1 point) No nuclei in human blood cells 62. Describe the Kastle-Meyer Test and the chemical reasoning for why it works. (3 points) The test is used to identify if a substance has blood in/on it using pH. (1 point) The indicator phenolphthalein is used because it turns pink in basic solutions (1 point), and because blood is slightly basic, a solution with blood in it will turn pink. (1 point) 63. While blood does not fluoresce under ultraviolet light without the assistance of luminol or other chemicals, why do certain other bodily fluids (e.g. saliva and semen) fluoresce under UV? (1 point) They contain compounds that absorb the energy from ultraviolet waves and reemit it at a longer, visible wavelength a. What is the name of the most common fluorescing molecule in bodily fluids? (1 point) tryptophan b. To what class of organic compounds does the answer to 63a belong? (1 point) amino acids DNA Analysis 64. Draw and label a simple diagram of a nucleotide. (3 points) 1 point for phosphate group, 1 for sugar, 1 for nitrogenous base 65. Classify A, G, C, T, and U as purines, pyrimidines, or neither. (3 points) 1 point for listing correct purines, 1 point for listing correct pyrimidines, 1 point for not listing anything under “neither” Purines _________A and G___________ Pyrimidines __________C, T, and U__________ Neither __________none__________ 66. From which biological parent can one’s mitochondrial DNA be traced back to? Why? (2 points) Carried through maternal lineage (traced back to mother) (1 point) because the mitochondria in mammalian sperm are usually destroyed by the egg cell after fertilization (1 point) 67. A certain biological theory explains the origin of chloroplasts and mitochondria in eukaryotic cells. Name this theory and use it to explain why mitochondria have separate DNA from the rest of a cell’s DNA. (2 points) Endosymbiont/endosymbiosis theory (1 point); states that a eukaryotic cell merged with a prokaryote and they developed a symbiotic relationship with the prokaryote (which has its own DNA) later becoming the mitochondria (1 point) 68. ____C____Which of the following statement about chromatography and electrophoresis is TRUE? (1 point) A. In chromatography, heavier, more-polar proteins travel farthest. B. In electrophoresis, a sample of no more than 10 base pairs is needed for accurate results. C. DNA electrophoresis can be used as a step to identify which species a sample came from. D. DNA electrophoresis will 100% accurately identify the person a DNA sample came from, since no two people have exactly the same DNA (excepting identical twins). E. All are true. 69. Which of the following is/are NOT a suitable source of DNA polymerase for PCR: T. aquaticus, P. furiosus, E. coli? Why not? (2 points) 1 point for identification, 1 for explanation E. coli; DNA polymerase from E. coli is not thermostable enough for the high temperatures of PCR 70. Which of the suspects’ DNA (find in suspect info) matches the crime scene DNA (to the right)? (1 point) Monica Geller 71. Rank these DNA bands produced by gel electrophoresis from smallest (1) to largest (6) molecular weight. (3 points) 0.5 points per correct letter 1___F___ 2___C___ 3___E___ 4___D___ 5___B___ 6___A___ 72. In what direction does the charge in gel electrophoresis run, starting from where the wells are loaded? From _____negative_____ to _____positive_____. (2 points) Finger 1 (R thumb) 2 (R index) 3 (R middle) 4 (R ring) 5 (R pinky) 6 (L thumb) 7 (L index) 8 (L middle) 9 (L ring) 10 (L pinky) Value (Given when finger has whorl) 16 16 0 8 0 0 0 0 1 0 Primary classification ______25/18______ (must be this exact fraction, can’t be decimal or simplified) Calculations: Primary classification = numerator value / denominator value = 25/18 Numerator value = (sum of all even finger values) + 1 = (16 + 8) + 1 = 25 Denominator value = (sum of all odd finger values) + 1 = (16 + 1) + 1 = 18 80. Label these types of fingerprints as patent, latent, or plastic. Define each type. (6 points) 1 point per correct type, 1 point per correct definition (awarded as long as the definition matches the type, regardless of whether or not the fingerprint type ID was accurate) Fingerprint Type Definition Patent Can be easily seen Plastic 3D print made in soft material (under alternate light source) Latent Typically invisible fingerprints made by deposit of perspiration or body oils 81. When developing latent prints, why might it NOT be a good idea for dusting be used as the first method? (2 points) Powders can contaminate evidence (1 point) & ruin opportunity to perform other techniques (1 point) that could turn up a hidden print or additional information 82. Identify each of the following patterns of fingerprints. Assume all prints were from suspects’ left hands. (4 points total, 0.5 points each) Sample Fingerprint Pattern Sample Fingerprint Pattern A Accidental whorl E Ulnar loop B Central pocket loop F Arch C Double loop whorl G Whorl D Radial loop H Tented arch