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Forensic Science - 2023 > Exam #3 > Flashcards

Exam #3 Flashcards

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1
Q

The Marquis Reagent was used on drug evidence and it turned purple. The drug being tested could be:

A

heroin

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2
Q

The Dillie-Koppanyi reagent is useful in screening for:
Marijuana.
Amphetamines.
Barbiturates.
Opiates

A

barbiturates

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3
Q

Duquenois-Levine solutions were used on a sample and the chloroform layer turned purple. This suggests that the tested substance is:

A

marijuana

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4
Q

Scott Test solutions can indicate the presence of:

A

cocaine

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5
Q

The specificity of microcrystalline tests is ________ the specificity of color tests.

A

greater than

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6
Q

Which type of test would logically be used first by the drug analyst?

A

color

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7
Q

Which techniques allows for both separation and specific identification of a questioned mixture of substances?

A

gas chromatography and mass spec

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8
Q

Which absorption spectrum is equivalent to a “fingerprint” of a substance and can be used for identification purposes?

A

IR (infrared)

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9
Q

A compound can tentatively be identified by gas chromatography from its:

A

retention time

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10
Q

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.

A

determine colors of a compound

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11
Q

Which chromatographic process would be LEAST likely to be utilized in the crime lab?
HPLC
GC
TLC
Paper chromatography

A

paper chromatography

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12
Q

TLC uses ________ as its moving phase.

A

liquid

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13
Q

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

A

all of the above

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14
Q

The administration of which drug eliminates an addict’s desire for heroin?
Codeine
Methadone
OxyContin
Morphine

A

methadone

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15
Q

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.

A

cost of the drug

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16
Q

Barbiturates act to:
Promote relaxation.
Create a feeling of well-being.
Produce sleep.
All of the above

A

all of the above

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17
Q

Methamphetamine is a:

A

stimulant

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18
Q

Cocaine is a(n):

A

stimulant

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19
Q

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

A

all of the above

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20
Q

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

A

all of the above

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21
Q

The use of which drug will NOT lead to physical dependence?
Heroin
Alcohol
Barbiturates
Cocaine

A

cocaine

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22
Q

Most narcotics are:
Depressants to the central nervous system.
Physically addicting.
Obtained from opium.
All of the above

A

all of the above

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23
Q

Which is NOT derived from opium?
Heroin
Morphine
Codeine
Marijuana

A

marijuana

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24
Q

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

A

all of the above are factors

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25
The rate of alcohol absorption on a full stomach is ________ the rate of absorption on an empty stomach.
less than
26
Alcohol is eliminated from the body chemically unchanged in: Breath Urine Perspiration All of the above
all of the above
27
Alcohol is oxidized in the body primarily in:
the liver
28
The blood alcohol concentration level for being presumed to be legally "Under the Influence" in most states is:
0.08%
29
The amount of alcohol absorbed through the stomach walls is ________ the amount of alcohol absorbed through the walls of the small intestine.
less than
30
There is a(n) ________ relationship between the amount of alcohol in the blood and that in the alveolar breath.
direct
31
Field sobriety tests do NOT include: Performance of sit ups. Walk and turn. One leg stand. Horizontal gaze nystagmus.
performance of sit ups
32
What is Locard’s Principle?
every contact leaves a trace
33
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
34
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
35
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
36
How do you determine the body area that a hair originated?
length of hair diameter of hair presence of medulla
37
Where is the following hair from: smaller diameter uniform pigment fragmented medula
scalp
38
Where is the following hair from: continuous medulla coarse wiry shows buckling uneven diameter
pubic
39
Where is the following hair from: blunt edges coarse wide medulla triangle cross section
beard
40
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
41
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
42
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
43
What test allows you to test if a fiber is natural or synthetic?
burn test
44
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
45
How has mass production limited the value of fiber evidence?
limits the ability to narrow down the source when found at crime scenes
46
What physical characteristics of fiber might help an examiner identify it?
color diameter cross section (shape)
47
Name two analytical devices used by forensic scientists to determine the class of a fiber.
microspectrophotometry microscope
48
How can microspectrophotometry and chromatography be used to analyze fiber evidence?
micro: color and absorbance chromo: separates fibers and dye composition
49
What are two important things to remember about samples when using gas chromotography?
must be only polar and heat safe
50
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
51
What is a stationary phase and what is a mobile phase?
stationary - solid mobile - gas and liquid
52
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
53
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
54
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
55
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
56
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
57
Do all molecules absorb the same wavelengths of light? How is this helpful in forensics?
no selective absorption helps to ID molecules
58
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
59
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
60
What affects drug toxicity?
tolerance how much was ingested how it was ingested what else is in your system
61
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)
62
What group does this drug belong to: Unknown drug A causes a marked alteration in thought processes, perceptions, and moods.
hallucinogens
63
What group does this drug belong to: Unknown drug B causes increased alertness and a feeling of well-being.
stimulants
64
What group does this drug belong to: Unknown drug C causes fatigue, relaxation, and a feeling of well-being.
narcotics
65
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
66
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
67
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
68
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
69
What is the order and type of test used to examine paint samples?
gas chromo then mass spec or IR spec
70
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
71
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
72
What three features of paint does a forensic scientist compare using a microscope?
color color layer sequencing surface texture
73
What is the greatest shortcoming in using layer structure to analyze paint evidence?
it shows various materials within the paint
74
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
75
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
76
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
77
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
78
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
79
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
80
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
81
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
82
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
83
Human hair can only be what pattern?
imbricate
84
What is postmortem toxicology?
how the levels play a role in death
85
What is human performance toxicology?
measure alcohol presence and estimate how a person will behave
86
What are pharmaco-kinetics?
science of how drugs move in and out of the body these also effect the nature of dependency
87
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
88
Explain the difference between psychological and physiological need in terms of drugs?
psych - emotional need - escape reality phys - physical need - withdrawal symptoms
89
What is qualitative analysis?
what is it
90
What is quantitative analysis?
how much of it is there
91
What are excipients?
an inactive carrier for a drug that often has similar properities
92
What are diluents?
used to reduce the amount of pure drug and often look like the drug

Forensic Science - 2023 (3 decks)

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