Forensic Science Final Review

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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.

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

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