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Forensic Science - 2023 > Exam #3 > Flashcards

Exam #3 Flashcards

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
Q

The rate of alcohol absorption on a full stomach is ________ the rate of absorption on an empty stomach.

A

less than

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26
Q

Alcohol is eliminated from the body chemically unchanged in:
Breath
Urine
Perspiration
All of the above

A

all of the above

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27
Q

Alcohol is oxidized in the body primarily in:

A

the liver

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28
Q

The blood alcohol concentration level for being presumed to be legally “Under the Influence” in most states is:

A

0.08%

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29
Q

The amount of alcohol absorbed through the stomach walls is ________ the amount of alcohol absorbed through the walls of the small intestine.

A

less than

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30
Q

There is a(n) ________ relationship between the amount of alcohol in the blood and that in the alveolar breath.

A

direct

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31
Q

Field sobriety tests do NOT include:
Performance of sit ups.
Walk and turn.
One leg stand.
Horizontal gaze nystagmus.

A

performance of sit ups

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32
Q

What is Locard’s Principle?

A

every contact leaves a trace

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33
Q

Understand and describe the regions of hair, and be able to apply this to the identification and comparison of hair samples.

A

cuticle - outer scale covering
cortex - inner hair region
medulla - middle of the cortex

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34
Q

What are the growth phases of hair?

A

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

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35
Q

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.

A

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

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36
Q

How do you determine the body area that a hair originated?

A

length of hair
diameter of hair
presence of medulla

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37
Q

Where is the following hair from:
smaller diameter
uniform pigment
fragmented medula

A

scalp

38
Q

Where is the following hair from:
continuous medulla
coarse
wiry
shows buckling
uneven diameter

A

pubic

39
Q

Where is the following hair from:
blunt edges
coarse
wide medulla
triangle cross section

A

beard

40
Q

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?

A

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
Q

Be able to describe how fibers are useful at crime scenes.

A
  • link a person to their presence there
  • provide class characteristics
  • determine how many people were there
  • clump presence could indicate fighting or scratching
42
Q

What allows you to tell if a fiber is natural or synthetic?

A

natural: imbricate - patterns of hair - color - variable (boring) cross section
synthetic: no medulla - more uniform - no DNA - consistent and unique cross section

43
Q

What test allows you to test if a fiber is natural or synthetic?

A

burn test

44
Q

What is mitochondrial DNA and why is it useful in analyzing hair samples?

A

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
Q

How has mass production limited the value of fiber evidence?

A

limits the ability to narrow down the source when found at crime scenes

46
Q

What physical characteristics of fiber might help an examiner identify it?

A

color
diameter
cross section (shape)

47
Q

Name two analytical devices used by forensic scientists to determine the class of a fiber.

A

microspectrophotometry
microscope

48
Q

How can microspectrophotometry and chromatography be used to analyze fiber evidence?

A

micro: color and absorbance
chromo: separates fibers and dye composition

49
Q

What are two important things to remember about samples when using gas chromotography?

A

must be only polar and heat safe

50
Q

Chromotography is a ____________ test that allows you to analyze ____________ sample(s) at once through the process of ________________.

A

non-confirmative test
multiple samples
splitting the samples while they are moving

51
Q

What is a stationary phase and what is a mobile phase?

A

stationary - solid
mobile - gas and liquid

52
Q

Why are drugs scheduled? What is the difference between a schedule I and a schedule V drug?

A

to rank them based on potential for abuse and dependance

schedule I - dependent more quickly
schedule V - least likely to become dependent

53
Q

What two goals must laboratory testing accomplish to positively identify a drug?

A

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
Q

How does a color test work? What is the main limitation of a color test for identifying drugs?

A

a chemical reagent turns it into a specific color when brought in contact with another drug

55
Q

Describe how a microcrystalline test works.

A
  • 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
Q

What is spectroscopy? How is it useful in forensics?

A

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
Q

Do all molecules absorb the same wavelengths of light? How is this helpful in forensics?

A

no

selective absorption helps to ID molecules

58
Q

What are the two types of confirmative tests for molecules? How do they identify molecules?

A

IR - measures vibrations
Mass Spec - high energy electrons collide with material producing charged ions

59
Q

What types of additives are found in street drugs? (excipient, diluent)

A

fetonayl

deadly chemicals that make mass producing drugs easier

has a different chemical reaction than pure drugs would

60
Q

What affects drug toxicity?

A

tolerance
how much was ingested
how it was ingested
what else is in your system

61
Q

Describe and explain some examples of drug uptake. Give an example for each route of uptake.

A

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
Q

What group does this drug belong to:
Unknown drug A causes a marked alteration in thought processes, perceptions, and moods.

A

hallucinogens

63
Q

What group does this drug belong to:
Unknown drug B causes increased alertness and a feeling of well-being.

A

stimulants

64
Q

What group does this drug belong to:
Unknown drug C causes fatigue, relaxation, and a feeling of well-being.

A

narcotics

65
Q

Why can the breathalyzer be used to determine BAC levels?

A

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
Q

List at least three factors that determine the rate at which alcohol is absorbed into the bloodstream.

A

stomach content
amount consumed
frequency/ how quickly it was ingested

67
Q

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?

A

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
Q

Why is it necessary to follow a positive screening test for drugs with a confirmation test? What is the confirmation test of choice?

A

b/c many drugs have similar characteristics so it can be hard to tell at first

mass spec

69
Q

What is the order and type of test used to examine paint samples?

A

gas chromo

then

mass spec or IR spec

70
Q

What is a trace element and why are trace elements important in analyzing physical evidence?

A

small quantities of something

can establish the source of a material

71
Q

How does the way most automobile manufacturers paint their cars help in the forensic comparison of automobile paint?

A

they use different chemicals and layer their paint in specific orders that are unique to each manufacturer

72
Q

What three features of paint does a forensic scientist compare using a microscope?

A

color
color layer sequencing
surface texture

73
Q

What is the greatest shortcoming in using layer structure to analyze paint evidence?

A

it shows various materials within the paint

74
Q

How is pyrolysis gas chromatography used to distinguish one paint binder formulation from another?

A

paint chips are broken down by heat - vaporizes the chemicals

then

gas chromatography separates the components

75
Q

How can soil evidence be valuable even if the site of the crime has not been ascertained?

A

soil adheres to various objects (locards principal)

soil is trace evidence

no two patches of soil are the same

76
Q

What is a mineral and how can minerals be important in the comparison of soil samples?

A

minerals: elements/ byproducts or breakdowns

soil is unique to every area so it can help to pinpoint a location of a crime

77
Q

Summarize the video from class:

A

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
Q

Be able to describe the positive and negative results for the presumptive and confirmatory tests for semen and blood.

A

luminol can detect if blood had been washed away unlike the other tests that check for color

79
Q

If someone wants to do a test to see if blood types match at a scene, how would they do that?

A

put in antibodies to the sample to test for antagens

if there is a clot/clump/reaction that means the marker is present

80
Q

How does a forensic investigator test for semen at a crime scene?

A

using the Fast Blue test

if the results are purple in under 30 seconds then there is semen present

81
Q

List two commonly used color tests for blood. How does a luminol test differ from these tests?

A

Hemastix - blood in urine - green or orange means positive
Kastle–Meyer - positive turns pink

doesn’t ruin DNA in the sample

82
Q

What is acid phosphatase and how is it used by forensic scientists?

A

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
Q

Human hair can only be what pattern?

A

imbricate

84
Q

What is postmortem toxicology?

A

how the levels play a role in death

85
Q

What is human performance toxicology?

A

measure alcohol presence and estimate how a person will behave

86
Q

What are pharmaco-kinetics?

A

science of how drugs move in and out of the body

these also effect the nature of dependency

87
Q

What is synergism?

A

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
Q

Explain the difference between psychological and physiological need in terms of drugs?

A

psych - emotional need - escape reality
phys - physical need - withdrawal symptoms

89
Q

What is qualitative analysis?

A

what is it

90
Q

What is quantitative analysis?

A

how much of it is there

91
Q

What are excipients?

A

an inactive carrier for a drug that often has similar properities

92
Q

What are diluents?

A

used to reduce the amount of pure drug and often look like the drug

Forensic Science - 2023 (3 decks)

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