Exam #3 Flashcards
The Marquis Reagent was used on drug evidence and it turned purple. The drug being tested could be:
heroin
The Dillie-Koppanyi reagent is useful in screening for:
Marijuana.
Amphetamines.
Barbiturates.
Opiates
barbiturates
Duquenois-Levine solutions were used on a sample and the chloroform layer turned purple. This suggests that the tested substance is:
marijuana
Scott Test solutions can indicate the presence of:
cocaine
The specificity of microcrystalline tests is ________ the specificity of color tests.
greater than
Which type of test would logically be used first by the drug analyst?
color
Which techniques allows for both separation and specific identification of a questioned mixture of substances?
gas chromatography and mass spec
Which absorption spectrum is equivalent to a “fingerprint” of a substance and can be used for identification purposes?
IR (infrared)
A compound can tentatively be identified by gas chromatography from its:
retention time
Chromatography is NOT used to:
Separate molecules in a mixture.
Tentatively identify molecules.
Determine colors of a compound.
Aid in analysis of illicit drug preparations.
determine colors of a compound
Which chromatographic process would be LEAST likely to be utilized in the crime lab?
HPLC
GC
TLC
Paper chromatography
paper chromatography
TLC uses ________ as its moving phase.
liquid
Marijuana has potential use in which medical application?
Useful as a muscle relaxant
Lessening of nausea caused by anticancer drugs
Reduction of excessive eye pressure in glaucoma
All of the above
all of the above
The administration of which drug eliminates an addict’s desire for heroin?
Codeine
Methadone
OxyContin
Morphine
methadone
The pattern and intensity of dependency on a drug does NOT depend on the:
Frequency of administration.
Cost of the drug.
Dose and route of administration.
Individual’s rate of metabolism.
cost of the drug
Barbiturates act to:
Promote relaxation.
Create a feeling of well-being.
Produce sleep.
All of the above
all of the above
Methamphetamine is a:
stimulant
Cocaine is a(n):
stimulant
What is true about the “club drug” Rohypnol?
It results in loss of memory of what happened in the hours after ingestion.
It is odorless, colorless, and tasteless.
It is enhanced when combined with alcohol.
All of the above
all of the above
The Controlled Substance Act established five schedules of classification for substances based on the drugs:
Potential for physical dependence.
Medical value.
Potential for psychological dependence.
All of the above
all of the above
The use of which drug will NOT lead to physical dependence?
Heroin
Alcohol
Barbiturates
Cocaine
cocaine
Most narcotics are:
Depressants to the central nervous system.
Physically addicting.
Obtained from opium.
All of the above
all of the above
Which is NOT derived from opium?
Heroin
Morphine
Codeine
Marijuana
marijuana
Which is NOT a factor in determining the rate at which alcohol is absorbed into the bloodstream?
The alcoholic content of the beverage
The amount consumed
The presence or absence of food in the stomach
All of the above are factors
all of the above are factors
The rate of alcohol absorption on a full stomach is ________ the rate of absorption on an empty stomach.
less than
Alcohol is eliminated from the body chemically unchanged in:
Breath
Urine
Perspiration
All of the above
all of the above
Alcohol is oxidized in the body primarily in:
the liver
The blood alcohol concentration level for being presumed to be legally “Under the Influence” in most states is:
0.08%
The amount of alcohol absorbed through the stomach walls is ________ the amount of alcohol absorbed through the walls of the small intestine.
less than
There is a(n) ________ relationship between the amount of alcohol in the blood and that in the alveolar breath.
direct
Field sobriety tests do NOT include:
Performance of sit ups.
Walk and turn.
One leg stand.
Horizontal gaze nystagmus.
performance of sit ups
What is Locard’s Principle?
every contact leaves a trace
Understand and describe the regions of hair, and be able to apply this to the identification and comparison of hair samples.
cuticle - outer scale covering
cortex - inner hair region
medulla - middle of the cortex
What are the growth phases of hair?
anagen - growth phase - full set of DNA
catagen - shriveling up - some growth - possibly some DNA
telogen - resting phase - no growth - hair shaft falls out - only mightocandrial DNA
How can you differentiate between human and animal hair? You should be able to explain in great detail the differences between the cuticle, medulla and cortex in human an animal hair.
Both have an imbricate hair pattern
animals: cortex is closer to the medula and medula is thick and forms a pattern
humans: cortex is closer to the cuticle and the medula is thinner, more continuous, and sometimes doesn’t exist
How do you determine the body area that a hair originated?
length of hair
diameter of hair
presence of medulla
Where is the following hair from:
smaller diameter
uniform pigment
fragmented medula
scalp
Where is the following hair from:
continuous medulla
coarse
wiry
shows buckling
uneven diameter
pubic
Where is the following hair from:
blunt edges
coarse
wide medulla
triangle cross section
beard
How do you determine whether a hair fell out or was pulled out? What type of hair specimens are potentially the richest source of nuclear DNA and why?
follicles have the most DNA
pulled out hairs still have follicles, dead hairs do not
if there is no follicle, DNA is extracted by the root
Be able to describe how fibers are useful at crime scenes.
- link a person to their presence there
- provide class characteristics
- determine how many people were there
- clump presence could indicate fighting or scratching
What allows you to tell if a fiber is natural or synthetic?
natural: imbricate - patterns of hair - color - variable (boring) cross section
synthetic: no medulla - more uniform - no DNA - consistent and unique cross section
What test allows you to test if a fiber is natural or synthetic?
burn test
What is mitochondrial DNA and why is it useful in analyzing hair samples?
find the DNA in cells
connects people with the same maternal lineage
DOES NOT INDIVIDVALIZE but can help to narrow down a wider pool
How has mass production limited the value of fiber evidence?
limits the ability to narrow down the source when found at crime scenes
What physical characteristics of fiber might help an examiner identify it?
color
diameter
cross section (shape)
Name two analytical devices used by forensic scientists to determine the class of a fiber.
microspectrophotometry
microscope
How can microspectrophotometry and chromatography be used to analyze fiber evidence?
micro: color and absorbance
chromo: separates fibers and dye composition
What are two important things to remember about samples when using gas chromotography?
must be only polar and heat safe
Chromotography is a ____________ test that allows you to analyze ____________ sample(s) at once through the process of ________________.
non-confirmative test
multiple samples
splitting the samples while they are moving
What is a stationary phase and what is a mobile phase?
stationary - solid
mobile - gas and liquid
Why are drugs scheduled? What is the difference between a schedule I and a schedule V drug?
to rank them based on potential for abuse and dependance
schedule I - dependent more quickly
schedule V - least likely to become dependent
What two goals must laboratory testing accomplish to positively identify a drug?
identify characteristics of the drug they want to test for
test for that drug and make sure to separate it from other present substances
How does a color test work? What is the main limitation of a color test for identifying drugs?
a chemical reagent turns it into a specific color when brought in contact with another drug
Describe how a microcrystalline test works.
- series of chemicals put onto the sample
- when the chemicals react to the substance, you get specific crystals that you can then view under the microscope
What is spectroscopy? How is it useful in forensics?
test a solution by passing a beam through a tube of the solution
measures quantity of radiation based on what the materials absorb
makes determining a materials identity easier
Do all molecules absorb the same wavelengths of light? How is this helpful in forensics?
no
selective absorption helps to ID molecules
What are the two types of confirmative tests for molecules? How do they identify molecules?
IR - measures vibrations
Mass Spec - high energy electrons collide with material producing charged ions
What types of additives are found in street drugs? (excipient, diluent)
fetonayl
deadly chemicals that make mass producing drugs easier
has a different chemical reaction than pure drugs would
What affects drug toxicity?
tolerance
how much was ingested
how it was ingested
what else is in your system
Describe and explain some examples of drug uptake. Give an example for each route of uptake.
how a drug gets into the body
injection (needle) (first hand)
inhalation (breath) (first hand) (nose) (first and/or second hand)
absorption (skin) (second hand)
What group does this drug belong to:
Unknown drug A causes a marked alteration in thought processes, perceptions, and moods.
hallucinogens
What group does this drug belong to:
Unknown drug B causes increased alertness and a feeling of well-being.
stimulants
What group does this drug belong to:
Unknown drug C causes fatigue, relaxation, and a feeling of well-being.
narcotics
Why can the breathalyzer be used to determine BAC levels?
gas chromatography is used to analyze BAC
the amount of alcohol in your breath is relatively the same and can be converted to determine the amount of alcohol in your blood
List at least three factors that determine the rate at which alcohol is absorbed into the bloodstream.
stomach content
amount consumed
frequency/ how quickly it was ingested
Name and describe the process by which most alcohol is eliminated from the body. How is the remaining alcohol eliminated, and how is this useful in testing for alcohol?
metabolism: how the body breaks down food/drugs into energy
eliminated via blood, sweat, urine
liver does most of the work, respiratory system does the rest
Why is it necessary to follow a positive screening test for drugs with a confirmation test? What is the confirmation test of choice?
b/c many drugs have similar characteristics so it can be hard to tell at first
mass spec
What is the order and type of test used to examine paint samples?
gas chromo
then
mass spec or IR spec
What is a trace element and why are trace elements important in analyzing physical evidence?
small quantities of something
can establish the source of a material
How does the way most automobile manufacturers paint their cars help in the forensic comparison of automobile paint?
they use different chemicals and layer their paint in specific orders that are unique to each manufacturer
What three features of paint does a forensic scientist compare using a microscope?
color
color layer sequencing
surface texture
What is the greatest shortcoming in using layer structure to analyze paint evidence?
it shows various materials within the paint
How is pyrolysis gas chromatography used to distinguish one paint binder formulation from another?
paint chips are broken down by heat - vaporizes the chemicals
then
gas chromatography separates the components
How can soil evidence be valuable even if the site of the crime has not been ascertained?
soil adheres to various objects (locards principal)
soil is trace evidence
no two patches of soil are the same
What is a mineral and how can minerals be important in the comparison of soil samples?
minerals: elements/ byproducts or breakdowns
soil is unique to every area so it can help to pinpoint a location of a crime
Summarize the video from class:
the crime trifecta
how to link the victim, suspect, and crime scene all together
phone linked victim and suspect
description of the jeep linked the victim and the crime scene
the soil linked the suspect to the crime scene
Be able to describe the positive and negative results for the presumptive and confirmatory tests for semen and blood.
luminol can detect if blood had been washed away unlike the other tests that check for color
If someone wants to do a test to see if blood types match at a scene, how would they do that?
put in antibodies to the sample to test for antagens
if there is a clot/clump/reaction that means the marker is present
How does a forensic investigator test for semen at a crime scene?
using the Fast Blue test
if the results are purple in under 30 seconds then there is semen present
List two commonly used color tests for blood. How does a luminol test differ from these tests?
Hemastix - blood in urine - green or orange means positive
Kastle–Meyer - positive turns pink
doesn’t ruin DNA in the sample
What is acid phosphatase and how is it used by forensic scientists?
an enzyme found mostly in semen
when testing, if there is a purple result in less than thirty seconds it means this enzyme is present
Human hair can only be what pattern?
imbricate
What is postmortem toxicology?
how the levels play a role in death
What is human performance toxicology?
measure alcohol presence and estimate how a person will behave
What are pharmaco-kinetics?
science of how drugs move in and out of the body
these also effect the nature of dependency
What is synergism?
total effect on the body of two or more drugs taken together is greater than the effects would be if the drugs were taken separately
Explain the difference between psychological and physiological need in terms of drugs?
psych - emotional need - escape reality
phys - physical need - withdrawal symptoms
What is qualitative analysis?
what is it
What is quantitative analysis?
how much of it is there
What are excipients?
an inactive carrier for a drug that often has similar properities
What are diluents?
used to reduce the amount of pure drug and often look like the drug
