How can we help?

You can also find more resources in our Help Center.

172 terms

Forensic Science Final Review

STUDY
PLAY
Which of the following is not a layer of the hair shaft?
Follicle
Which part of the hair shaft is most resistant to chemical decomposition?
Cuticle
Which feature of hair most important in making species identification
Scale pattern
The number of hair scales pointing towards the tip of the hair is ____ the number of hair scales pointing towards the hair follicle
Greater than
Which type of crime is least likely to be solved with the use of fiber evidence?
Bombing
Pigment granules that impart hair with color are found in the:
Cortex
The central canal running through many hairs is known as the:
Medulla
The medullary index of human hair is ___ the medullary index for most other animals
Less than
Medullae may be classified as being
Interrupted/Absent, continuous, fragmented
If a hair does not have a follicular tag, an expert witness is on best scientific footing when stating that:
A suspect hair comes from a particular animal species
Which race is most likely to have head hair with continuous medullae?
Mongoloid
A hair sample was examined and its medulla appeared to have a pattern described as resembling a string of earls. It was most likely from a:
Deer
The removal of an object or surface that was located between the origin of blood and the target surface during the bloodstain deposition leaves behind:
A void
Beard hairs are coarse and normally ____ in cross-section
Triangular
A human hair in cross-section appeared flat in shape. The facial origin
Negroid
In determining whether a hair sample originated from a male or a female, the most important consideration is:
The results of DNA analysis performed on the root structure
The presence of sheath cells on hair that has been pulled quickly form the head is ___ the presence of sheath cells on hairs that have been removed slowly form the scalp
Greater than
Nuclear DNA typing can be most successfully accomplished on hairs that have been removed during which of stage of growth?
Anagenic
The conviction of Ennis Cosby's killer was aided by the DNA analysis on a hair that that was crucial evidence in that case. This hair:
Belonged to the killer and was found in his cap with which he had wrapped the murder weapon before discarding it.
In what stage can a hair most readily be removed from the scalp?
Telogenic
Combustion occurring at the surface of a solid describes:
Glowing combustion
Telltale signs of arson include:
Separate points of origin, streamers connecting burned areas, the presence of accelerant containers, trails of burn patterns
Factors that can contribute to abnormal observations at a fire scene include:
Stairways on elevator shafts, winds or drafts, secondary fires due to collapsing floors or roof, holes in the structure
The transfer of heat energy by the movement of molecules within a liquid or gas is:
Convection
The rapid combination of oxygen with a fuel, which produces a noticeable release of energy is called:
Ignition
The minimum temperature at which a fuel will spontaneously ignite is called:
Ignition temperature
The minimum temperature at which a liquid fuel will produce enough vapor to burn is called the
Flash point
The concentrations at which a vapor to fuel mixture in the air is capable of burning is referred to as the
Flammable range
The movement of heat through a solid object is known as
Conduction
Heat energy can ignite distant objects through the transmission of
electromagnetic energy
Materials that have electrons firmly attached to their molecules
Are poor conductors of heat
When investigators search a fire scene, the first focus must be on
Finding the origin of the fire
Hydrocarbon accelerants can be detected by
A portable detector and trained dogs
What instrumentation is considered the most sensitive are reliable for detecting and characterizing flammable residues
GC
A fuel can only achieve combustion
The gaseous state
The decomposition of organic matter by heat describes
Pyrolysis
The chemical reaction associated with a fire is
Oxidation
A natural heat producing process that may give rise to a fire is
Spontaneous combustion
Gasoline residues are best characterized by
Gas chromatography
All combustible fuels simultaneously igniting to engulf a structure in flames is known as
Flashover
What are the four layers of the hair shaft?
Cuticle, scales, cortex, and the medulla
Which part of the hair shaft is most resistant to chemical decomposition?
Cuticle
Which feature is most important when making hair?
Scale Pattern
The number of hair scales pointing towards the tip of the hair is:
Greater than the number of scales pointing towards the follicle
What is a crime that is least likely to be solved using fiber evidence?
Bombing
Pigment granules that impart hair with color are found in the:
Cortex
The central canal running through many hairs is known as the:
Medulla
The medullary index of human hair is:
Less than the medullary index for most other animals
Medullae may be classified as being?
Interrupted/absent, continuous, fragmented
If hair does not have a follicular tag, an expert witness is on best scientific footing when stating that:
A suspect hair comes from a particular animal species
Which race is most likely to have head hair with continuous medullae?
Mongoloid
A hair sample was examined and its medullae appeared to have a pattern described as resembling a string of pearls. It was most likely from a:
Deer
The removal of an object or surface that was located between the origin of blood and the target surface during the bloodstain deposition leaves behind?
A void
Beard hairs are coarse and normally:
Triangular in cross-section
A human hair in cross-section appeared flat in shape. The racial origin was most likely?
Caucasian
In determining whether a hair sample originated from a male of female, the most important consideration is:
The results of the DNA analysis performed on the root structure
The presence of sheath cells on hair that has been pulled quickly from the head is?
Greater than the presence of sheath cells on hairs that have been removed slowly from the scalp
Nuclear DNA typing can be most successfully accomplished on hairs that have been removed during which stage of growth?
Anagenic
The conviction of Ennis Cosby's killer was aided by the DNA analysis on a hair that was crucial evidence in the case, this hair belonged to who?
The killed and was found in his cap with which he had wrapped the murder weapon before discarding it.
how many hairs should be collected from the scalp to ensure representative sampling?
50 hairs
what are three phases of hiar growth
anagen catogen telogen
human hair generally has an ____ medullae
absent
the ____ contains pigment granuels responsible for hiar color
cortex
what phase of growth cana criminilist obtain DNA from?
anagen
hair
an appendage of the skin that grows from an organ known as the hair follicle
can you tell the sex from morphological featurs of a hair strand?
no
where is mDNA found?
it is found in the mitochondira and it is inherited from the mother.
how can you tell when a hair is forcibly removed?
it has a follicular tag attached to it
3 layers of the skin?
dermis , epidermis, and adipose tissue
which layer of the skin is responsible for insulating the body?
the epidermis
what are the names of the 2 types of lenses on a comparision microscpose
comparitive and objective
how much does a hair grow per month?
1 cm
how would an investigator preserve evidence from a suspected arson fire?
in an airtight container
endothermic reaction
a chemical reaction in which heat is absorbed
work
force X distance
oxidation
combo of 02 and another substance to make a new substance
pyrolysis
chemcial decomposition of a solid
2 factors that affect the rate of a chemical reaction
1. physical state of a fuel.
2. fuel temperature
where is energy stored in a molecule
mitchondira.
3 ways a criminilist can ascertain that a fire was started by an arsonist
1. accelerants left behind
2. finding an origin or multiple origins
3. streamers connecting burned areas
flashpoint
lowest temperature at which a liquid fuel can produce enough vapor to burn
spontaneous combustion
caused by a natural heat producing process in the presence of air and fuel. example is a forest fire and hay buring in a barn.
glowing combustion
occurs on the surface of a solid in the absence of heat and light. ex- charcoal on a grill.
rust
Fe03
magnesuim oxide
mgo
conditions needed to initiate and sustian combustion
1. fuel
2. oxegyn
3. heat
conduction
transfer of heat through movement of molecules in a solid object
radiation
tranfer of heat from a hotter surface to a cooler surface
convection
tranfer of heat through movement of molecules within a liquid or gas.
the amount of spatter from a blood droplet falling on a hard non porus surface is _____ than that of a srop of blood falling onto a softer porus surface
less than
the pointed end of a bloodstain always faces
in the direction of travel
the most common type of bloodstain pattern found at a crime scene is ?
impact spatter
by counting and pairiingthe patterns of a _____ pattern an investigator can estimate the minimum amount of blows inflicted on the victim
cast off
the intersection of straight linnes through a long axis of serveral bloodstains in an impact spatter pattern ilustrates the ___ of the pattern
area of convergence
at a crime scene, the srting method is used to find the ____ of an impact spatter pattern
area of origin
the deposition of bacwards spatter produced by a gunshot wound is determined by...
the location of the injury
the location of the surface of deposition
the distance between the victim and the muzzle
the size of the wound created
the pressure of the pumping of oxygenated blood out of an injury ccauses brihgt red colored blood to spurt out and form what?
arterial spray
ane expirated blood pattern at a crime scene can be identified by?
bubbles of oxegyn within the pattern
contact pattern
when an object wiht blood on it touches an object without blood on it
widely spaced bloody shoeprints with satellitespatter between them were likey deposited by a person who was what?
RUNNING
the direction of a ______ maay show movements of objects or bodies while the pattern was still forming or after the blood has dired.
flow pattern
the approx dring time of a pool of blood can be used to estimate timing pf events at a crime scene and is dependent on what?
enviormental condition
proper location and documentation of bloodstain patterns at the crime scene is the responsibility of?
criminilists and specialists
bloodstain diameter _____ as height increases
increases
area of origin
in a three dimensional space illustrates the position of the victim or suspect when the stain producing event took place
three types of blood vessels
artery capillary and veins
approx drying time of a blood droplet
50 seconds
list the four blood groups
a b ab o
two ways to identify expirated blood
more diluted wiht saliva - lighter color
more oxegyn in the blood
6 ex of renewable energy
1geothermal
2hydropower
3solar energy
4biomass
5wind
6tidal
4 ex of biomass
1fuelwood
2solid waste
3crop residues
4energy plantations
msot corn in the us is produced for what?
FOOD
less developed countires use what as thier main fuel source?
biomass
what gas is made when animal waste is broken down on farms to from energy?
methane
GLOCOSE
c6h1206+602-> 6c02+6h20
2 main crops growm fro enery use?
corn and sugar cane
3 gorges dam
largest hydroelectric dam in the world
cfc
chloro floro carbon
solar panels
people put on thier roofs to trap solar power
negative effects of building wind turbines?
they need to be built in an area with lots of wind. birds die when they fly thorugh it.
worlds most abundant fossil fuel
coal
anaerobic respiration
c6 h12 06 ->2c2h5oh+2c02+energy
photosynthesis
6c02+6h20-> c6h1206+602
cases that cause global warming
methane and c02 ( greenhouse gases)
viscosity
viscosity is the reluctance of a liquid to flow. water has a low viscosity, while syrup has a high viscosity.
specific heat capacity
the time it takes for a liquid to heat and cool. water has a high shc meaning it takes a long time to heat and cool.
density
d=mXv waters density is 1g/cm3
eutrpphication
when things like nitrates and phospates are added into bodies of water in too much quantity and spark the growth of too much algae the algaes up all the oxegyn int eh water adn causes marine life to suffocate
capillary action
when water on the surface of an object is being pulled only downwards not up, so if carefully placed, something with a higher density than water can rest on top of water ( like insects) because of the tension on the surface ( surface tenion)
hydrogen bonds
force of attraction between a hydren atom of one molecule of water and the oxegyn, nitrogen or fourine.
what are the five major stepsin water purification
screening filtration settling florination and chlorination
condensation
the trasformation froma gas to a liquid.an example would be water on the outside of a glass.
sublimation
the transformation froma gas to a solid without going through the liquid phase. an example is dry ice (solid co2)
salinity
he percentage of salt in water or a liquid, a human can comsume water with a percentage of 2.2% and oceans have 3.5
2 ways to reduce the amount of salt in water
1. distill it
2.freezing
boiling point of water C
100
freezing point of water in C
0
BOD
biological oxegyn demand
EPA
enviormental protectian agency
OPEC
organization of petroleum exporting countries
FDA
food and drug administration
describe an unusual property of water when it freezes
an ususual property of water when it freexes is that it expands and that it is less dense when it is in its solid form.
what is the name of the illness associated with high levels of mercury in the fish in japan?
mininata
what is a saturated solution
a solution that cannot dissolve anymore solute
what contains more oxegyn- warm wter or cold water
cold water
water is known as the _____ solvent becuase it dissolves more substances
universal
the human kidneys are unable to concentrate more than a ___ salt in the urine.
2.2%
what are the three main components on urine
salt water urea
what material do marine animals use to make their shells?
sodium bicarbonate
degine alloy and give an example?
an alloy is a compound that contains 2 or more different metals . an example is steel which contans cobalt nickel and iron.
name 2 gases that are very harmful which are found in car exhausts?
nitrogen dioxide and carbon monoxide
biodegradeble
a substance that will funny break down into the earth adn example is frut and vegetable skin
what is the differnece between adsorbtion and absorption?
absorption is when something is being pushed into the substance absorbing. an example is a sponge.
adsorption it when water attaches to the surface of an object.
why do icebergs contain very little salt?
icebergs contain very little salt because when you freeze something it decreases the amount of salt in the substance and becuase icebergs are cold they have little salt.
name the two most common sources that are responsible for the rapid overgrowth of algae in rivers and lakes
phosphates and nitrates
what process would you use in the lab to separate soil and water?
settling
what process would you use in the lab to separate alcohol and water?
filtration
a person must undergo ______ if thier kidneys fail while they wait for a kidney transplant.
dialysis
the pH of acidic water is ___ than 7
less
what is the name of the device found in the exhaust of a car that removes nitrogen oxide and carbon monoxide from the car exhaust fumes
filter.
fossil fuels
decayed animals plants and microoganisms from millions of years ago
3 examples of fossil fuels
oil coal and natural gas
what is the major sourc of energy for every ecosysten
sunliGHT
the first fossil fuel
coal
the invention of the_____ was central to the industrial revolution
steam engine
list three other industries that flourished due to the automobile industry
steel oil and coal.
oil removed from the ground?
crude oil
in tokyo, what much a buyer prove before they can buy a car
they must prove that they have a place to park it
which country uses the most energy per capita?
cananda
which country uses the most energy for transportation needs
US
5 forming members of OPEC
saudia rabia iraq iran kuwait
which country produces the most oil?
saudia rabia