Forensics General Knowledge Flashcards
What is the definition of chromatography?
The separation of mixtures into their constituents
What is the difference between a solvent and a solute?
In a mixture, the solute is the substance that is dissolved into the solvent
What ratio does Rf represent?
Distance traveled by pigment : Distance traveled by solvent
Write the balanced chemical reaction made between Calcium Carbonate and Hydrochloric
Acid.
CaCO3 + 2HCl —> CaCl2 + CO2 + H2O
What protein is hair primarily composed of?
Keratin
How many ridges does the average human adult have on one finger?
150
What does Rf stand for?
Retention Factor
What causes fingerprint ridge patterns?
Amount and location of volmer pads in thick skin
Name two uses of Calcium Nitrate.
Any combination (may be more): fertilizer, ice melt, glass manufacture, meat preserve, reagent, catalyst in rubber production, pyotechnic
What is the full name for the polymer abbreviated using the letters LDPE?
Low Density Polyethylene
Draw the chemical structure for LDPE.
[look at key]
Please name two uses for LDPE.
Any combination (may be more): addition, bread bags, frozen food bags, grocerybags
What is the chemical basis for Iodine fuming (Ninhydrin)?
Iodine reacts with oils/fats, Ninhydrin reacts with amino acids
What is the chemical basis for dusting (S.P.R.)?
Fatty acids/lipid reaction
What is the full name for the polymer abbreviated using the letters PP?
Polypropylene
Draw the chemical structure of PP.
[look at key]
Please name two uses for PP.
Dishwasher safe containers, yogurt containers, margarine tubs, medicinebottles, bottle tops
What does DNA stand for?
Deoxyribonucleic Acid
Name two uses of Lithium Chloride.
Bipolar disorder medication, antidepressants, brazing flux for aluminum in automobile parts
What insect is usually the first to come into contact with a dead body?
Blow-flies
Define the meaning of a diatomic element.
Elements that make a diatomic molecule with only the atoms of their element.
Please list all elements that can be diatomic.
Hydrogen, Nitrogen, Oxygen, Fluorine, Chlorine, Bromine, Iodine
What are the four nucleotides found in DNA?
Adenine, Guanine, Thymine, Cytosine
List two names for the chemical powder NaHCO3.
Sodium Bicarbonate and Sodium Hydrogen Carbonate
What is the full name for the polymer abbreviated using the letters PVC?
Polyvinylchloride
Draw the chemical structure of PVC.
[look at key]
Please name two uses for PVC
package film, unplasterized foam, water pipes, plumbing, phonograph records,
synthetic floor tiles, credit cards, plastic raincoats, shower curtains
What percentage of the population has arched fingertips?
5%
Describe two uses of Boric Acid
Antiseptic, electrophoresis, insecticide, fiberglass manufacturing, pyrotechnics,
industrial manufacturing, nuclear power
What is the full name for the polymer abbreviated using the letters PETE?
Polyethylene Terephthalate
Draw the chemical structure of PETE.
[look at key]
Please name two uses for PETE.
Bottles, peanut butter jars, salad dressing bottles, non-breakable bottles
What type of molecule is being tested for in ABO blood testing?
protein
What does AFIS stand for?
Automated fingerprint identification system
What percentage of the population has looped fingerprints?
70%
What percentage of the population has whorl fingerprints?
25%
How is DNA replicated in a laboratory?
Using a Polymerase Chain Reaction (PCR) sequence
What property of the nucleotides makes DNA replication possible?
Adenine only matches to Thymine (and vice versa) and Cytosine only matches to
Guanine (and vice versa)
What are the four steps of Mass Spectrometry?
Ionisation, Acceleration, Deflection, Detection
What are the two primary categories of fibers?
Natural and Synthetic
What is the full name for the polymer abbreviated using the letters PMMA?
Poly(methyl methacrylate)
Draw the chemical structure of PMMA.
[look at key]
Please name two uses for PMMA
plexiglass, barrier at ice rinks, basketball backboards
What is another name for Fourier transform ion cyclotron resonance mass spectrometry?
Fourier transform mass spectrometry
What does m/z mean in mass spectrometry?
mass-to-charge ratio
Other than in the hair, where can the protein that primarily comprises hair be found in the
human body?
nails, outermost layer of skin
What is the full name for the polymer abbreviated using the letters PS?
Polystyrene
Draw the chemical structure of PS.
[look at key]
Please label the following diagram.
[look at key]
What is the name given to the 10-16 points of a fingerprint used to compare to a database?
minutiae
The unpredictable array of fine detail found on the pads of the hands and the feet are called what?
friction ridges
The first person to classify and document fingerprints in 1892 was:
Sir Francis Galton
A single ridge splitting into two ridges is called a:
bifurication
Fingerprints not visible to the naked eye are called:
latent
Prints on a porous surface such as paper were treated by turning them purple. The process used was probably:
ninhydrin saturation
Which of the following tests require heat to develop the print?
a. Cyano Acrylate Fuming
b. Silver Nitrate Misting
c. Iodine Fuming
d. Ninhydrin Saturation
e. A & B
f. B & C
g. A & C
h. A & D
h. A & D
Cyano Acrylate Fuming and Ninhydrin Saturation
Which of the following is not a recognized fingerprint pattern?
a. loop
b. whorl
c. delta
d. arch
c. delta
True or False?
It is impossible for an individual to have more than two different types of fingerprints.
False.
The common database used throughout the US to identify fingerprints is called:
AFIS
The 10-print card system developed in the early 1900s to classify fingerprints is called:
The Henry System
A fingerprint pattern that opens to the inside of the arm is called:
Radial
Rigor Mortise is the temporary stiffening of the joints. The typical duration of the process is:
3 hours to 72 hours after death
The science of fingerprint identification is also known as
Dactyloscopy
3-D fingerprints left in soft material such as wax or certain greases that identify ridge depths as well as width and length are called:
Plastic
In terms of crime scene investigations, what is luminol useful for? Explain the chemistry of how luminol works.
Luminol can be sprayed on a surface and will glow if blood stains are present. The central chemical in this reacion is luminol (C8 H7 O3 N3), a powdery compound made up of nitrogen, hydrogen, oxygen, and carbon. Criminalists mix the luminol powder with a liquid containing hydrogen peroxide (H2 O2), a hyrdroxide (OH-) and other chemicals, and pour the liquid into a spray bottle. The hydrogen peroxide and the luminol are actually the principle players in the chemical reaction, but in order to produce a strong glow, they need a catalyst to accelerate the process. The mxture is actually detecting the presence of such a catalyst, in this case, the iron in hemoglobin.
What is the most common blood type?
O+
What is the least common blood type?
AB-
Write one or two sentances that describes how a gas chromatography device works. Be sure to include the following terms in your description. elotion time mobile phase stationary phase inert gas adsorbant mixture
Gas chromatography is a technique by which a mixture can be separated based on differences in their affinity for an adsorbant stationary phase while being moved through a column by an inert gas which is considered the mobile phase. Substances which show increased affinity for the stationary phase will not travel as quickly through the column and will show an increased elution time. The hope is that these differences in affinity willl be great enough to acheive adequate separation.
Please name two uses for PS.
Disposable cutlery, plastic models, CD and DVD cases, smoke detectors, and foam drink cups.
