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Document Analysis
Presumptive Blood Test
Blood Typing
Chemiluminescence
Random
100
What item was spotted on the papers during our document analysis lab?
Marker ink
100
What is the name of the presumptive blood test we did in lab?
The Kastle-Meyer test
100
What are the 8 blood types we learned about in class?
A+, A-, B+, B-, AB+, AB-, O+, O-
100
What chemical is mixed with blood to generate a glowing reaction?
Luminol
100
What instrument is used to separate blood?
Centrifuge
200
What was the mobile phase and what was the stationary phase in the document analysis lab?
The mobile phase was the ethanol solvent. The stationary phase was the chromatography paper.
200
What term is used to describe a test result of (1) definitely not being a certain substance and (2) can probably be a certain substance?
Presumptive
200
What blood types can a person with blood type AB- donate to?
AB-, AB+
200
What element in the blood protein hemoglobin catalyzes the chemiluminescent reaction?
Iron
200
While performing a blood typing analysis on a human blood sample, a forensic scientist observes an agglutination reaction in the B antigen and Rh antigen wells. What blood type does the analyzed blood sample have?
B+
300
What does chromatography mean?
The separation of substances in a mixture
300
Name 2 reasons why the Kastle-Meyer test is performed at crime scenes instead of sending every possible bloodstain to the forensics lab.
The test is cheap, easy to do (simple/common materials needed), and provides a quick response.
300
What are 2 terms used to describe the development of a solid when two incompatible blood types are mixed?
Agglutination and precipitation
300
Name 1 chemical that can provide a false positive reaction
Bleach. Urine with low levels of blood. Stool with blood or peroxidase enzymes.
300
Name 3 properties that will allow molecules to separate during chromatography
Molecular size, molecular structure, and affinity to a medium
400
How was ink from the note extracted and analyzed in the document analysis lab?
The part of the note with the ink on it was cut out and placed in a test tube. A solvent consisting of water and ethanol was used to extract the ink from the note paper. The extracted ink was then spotted on the chromatography paper.
400
List 4 chemicals needed to perform the presumptive blood test. Spelling counts!
Possible blood sample, ethanol, phenolphthalein, and hydrogen peroxide
400
What are two possible genotypes for a person who has B antigens and Rh factor antigens on the surface of their red blood cells?
This person will have blood type B+. The two possible genotypes for this person are IB-IB and IB-IO
400
Provide 1 reason why crime scene investigators will not automatically spray luminol all over a crime scene when they suspect a crime involving blood has been committed.
The luminol can destroy other evidence (proteins, enzymes, and genetic markers). The chemiluminescent reaction fades quickly (about 30 seconds for most human blood stains). The environment needs to be dark (outdoors scenes during the daytime will not be desirable).
400
What chemical was used to create the IACS simulated hemoglobin solution?
copper (II) sulfate
500
What does the phrase like dissolves like mean? For credit, make sure your response includes these terms: polar, nonpolar, solute, and solvent
Nonpolar solutes will dissolve in nonpolar solvents. Polar solutes will dissolve in polar solvents.
500
Explain why the presumptive blood test cannot provide definitive test results when analyzing suspects' blood samples.
This test may yield positive results for animal blood as well as human blood. It can also yield a positive result for any substance that contains oxidizing reagents, such as the peroxidase enzyme found in broccoli and cauliflower. Because it cannot rule out the possibility of an unknown sample as being human blood, animal blood, or some vegetables, its result is considered presumptive.
500
Explain why a person with blood type O- is considered to be the universal donor. Your explanation must include these terms: A antigen, B antigen, Rh factor antigen.
A person with blood type O- is the universal blood donor because they do not have the A antigen, B antigen, or Rh factor antigen. Not having these antigens means that there is no possible way that an unintended dangerous agglutination reaction can occur during a blood transfusion.
500
Our luminol solution was prepared by dissolving the luminol powder in distilled water. Since luminol reacts in the presence of an oxidizing agent, name another chemical we've used in the lab that can be used to enhance the intensity of the blue color in a chemiluminescent reaction.
Hydrogen peroxide
500
Provide an explanation at the subatomic level for why a blue color is given off during a chemiluminescent reaction.
The blue color is given off when excited electrons return to their normal states