PCC 274 Exam 3

short tandem repeats (STRs) targeted for routine DNA casework belong to the:

nuclear genome

the number of STR loci required to be typed for forensic DNA casework in the US is:

20

the refractive index of a substance varies with:

its temperature, the color of the light passing through it, and the wavelength of the light passing through it (all of the above)

LASER stands for:

Light Amplification by Stimulated Emission of Radiation

what are the 2 main types of DNA variations?

sequence polymorphism and length polymorphism

What is the main ingredient in ordinary glass?

sand

which states did Ted Bundy kill his victims in?

Washington, Oregon, Colorado, Utah, and Florida

if an object is immersed in a liquid of greater density, it will:

float

Arson investigators must work quickly to collect evidence at a fire scene because:

accelerant residues may quickly evaporate, safety requirements may state that cleanup and salvage begin quickly, and accelerants in soil may quickly degrade (all of the above)

in current practice, simultaneous separation of multiple STR loci on a capillary electrophoresis instrument is achieved by:

differences in fluorescent dye associated with STRs, and differences in the amplified STR lengths (both)

a fuel can only achieve combustion in:

gaseous state

CODIS, the national DNA database of short tandem repeat (STR) profiles:

was created in 1994 and each state/territory uploads profiles of convicted offenders, does not permit searching of victim profiles, and is maintained at a national level by the FBI (all of the above)

the presence of three peaks (alleles) for at least one STR locus indicates a sample is:

from multiple sources/contributors

the four phases of fire progression are:

Incipient, emergent smoldering, free burning, oxygen-related smoldering

which chemical reaction is associated with fire?

oxidation

what is NOT an intensive property of matter?

weight

Movement of heat through a solid object is caused by:

conduction

The process of a glass prism separating sunlight into component colors is called:

dispersion

what is NOT true about primary explosives?

they are very stable

what info can quantitative PCR provide?

amount of DNA and quality of nuclear DNA

Which homemade explosive that has been used by terrorist org. in the Middle east?

TATP

what is a chemical used to synthesize the explosive TATP?

hydrogen peroxide

Pigment granules that impart hair with color are found in the:

cortex

A low explosive has a velocity of detonation less than:

1000 meters per sec

TATP chemical structure

circular Os with H3C and CH3 coming off it

the medullary index of the human hair is ________ the medullary index for most other animals

less than

IMS is an acronym that means:

Ion Mobility Spectrometry

in determining whether a hair sample originated from a male or female, the MOST important consideration is:

the results of the DNA analysis performed on the root structure

evidence collection of fire debris is collected in:

paint cans

What's the amount needed for traditional DNA typing?

1 ng

a fiber whose microscopic appearance includes being ribbon-like in shape (flat) with twists at irregular intervals is:

cotton

the anagen phase will last:

about 2 years/ 6 years

what are the four basic methods of heat production?

electrical, mechanical, nuclear, chemical

Nuclear DNA typing can be most successfully accomplished on hairs that have been removed during which stage of growth?

anagenic

DNA is a:

polymer

The PCR technique requires the use of a thermal cycler to:

copy DNA

plastic bags are suitable to store evidence suspected of containing explosive residues

false

a search of a fire scene must focus on finding the fire's point of origin

true

Bombs made of high explosives must be detonated by an initiating explosion.

true

secondary explosives are ultra-sensitive to heat

false

individual hairs can show variable morphological characteristics within a single individual

true

backdraft occurs at an explosive rate due to the extreme temps being fueled by the new oxygen

true

the first step in the forensic examination of fibers is to compare color and diameter

true

Ted Bundy escaped from prison three times

false

mitochondrial DNA is used to identify an individual with very high probability

false

the boiling point of a substance is a chemical property

false

it is possible to estimate when hair was last bleached or dyed by microscopic examination

true

Ted Bundy's mother believed Ted was innocent even after his execution

true

define intensive property and name two properties of matter

an intensive property is a property that is not dependent on the size of the object. 2 examples are density and solubility

describe the floatation method and explain what it is used for

used to find the density of glass. fragments are placed into a liquid that has an adjustable density, and that density is adjusted until the glass fragment is suspended in the middle of the liquid.

2 similarities and differences between Bundy and Gacy

Similarities: both active in politics and their communities, and both known for being charismatic and smart.

Differences: victim (young women/ boys) and MOs (kidnap and stab/lure to house and strangle)

sequence of impacts

A then B

three techniques used for elemental analysis of glass

XRF, SEM-EDS, ICP-OES, ICP-MS, LA, and LIBS

Ted Bundy MO and how was he arrested?

Bundy went after young women who looked like his ex-girlfriend. He would prey on their kindness and kidnap them, then take them to the woods and rape/stab/kill them. He would sometimes return and rape the decaying body.

He was arrested three times, but escaped the first two. The last time was in Florida, after he killed two people, he was recognized by his stolen car.

what distinguishes an explosion from combustion?

combustion is a chemical reaction that produces heat and gas slowly for a certain time period, whereas explosions are chemical reactions that produce heat and gas rapidly in an instant

name three ways DNA typing has been used

identification of suspects in forensic cases, identifying the father in paternity tests, and historical artifact analysis.