CHE 113 Final Exam review

What type of blood cell is involved in transporting hemoglobin to cells?

Erythrocytes

Quantatitative analysis focuses primarily on

How much of a substance is present in a sample

Matching key features found in an unknown sample with candidates from a very large pool of known possibilities is commonly referred to as

one-to-many matching

Can hairs from the same head have different morphological characterisitics?

Yes

How DNA works

- Nuclein acid carries genetic information (DNA & RNA) -Consists of a phosphoric acid molecule, five carbon sugr, nitrogen containing base

Electron Microscope

-A beam of electrons, instead of light, is used with an electron microscope -Magnify greater because wavelengths of electrons are much smaller than those of visible light

Visualizing prints for hard surfaces

-Aluminum dust: highly visible on dark and mirrored surfaces -Carbon black for white surfaces -Luminescent powders: fluoresce under ultraviolet light -Magnetic powder

Gel Electrophoresis

-Amplify DNA sample, react with restriction enzymes, prepare sample -Use elec. Current to move DNA pieces -Seperates DNA by fragment size -Smaller pieces travel the fastest

Can estimate time of death from?

-Body temp changes -Rigor mortis -Insect action -Stomach contents -Last known activity -Normal postmortem changes

DNA Analysis

-Collection of Sample -Separation and Purification of DNA -Amplification -Cutting/Separation of Fragments -Comparison and Analysis

Projected bloodstains

-Created when a blood source is subjected to an action greater than the force of gravity

Tandem Repeats

-DNA forms genes that code for proteins -Not all DNA codes for proteins -Intergene regions contain many A, T, C, G repeats called Tandem Repeats -Forensic DNA typing uses tandem repeats

Comparison Microscope

-Important tool for firearms examiner -Two compounf miscroscopes combined into one unit -When viewer looks through the eyepiece, a field divided into two equala parts is observed

Problems with Frye Standard

-Inflexible (and slow) for new developments or extensions of existing techniques and methods -Requires complete agreement in the scientific world

DNA Structure

-Info in the order of nucleotides in DNA can be transcribed and translated to direct the preparation of proteins in the cell -Every three nucleotides in DNA codes for one amino acid in the formation of a protein -Parts of DNA coding for proteins are called genes -DNA contains vert large parts that code for nothing known

Types of prints

-Latent prints: invisible to the naked eye and must be developed to see -Visible prints -Plastic prints: impression of fingerprints in soft media

Polarizing Microscope

-Light confined to a signle plane of oscillation is said to be polarized -Reduced glare by transmitting light in a vertical plane only

Hair: Class evidence

-Resistant to chemical decomposition and long-term structural stability -Can determine the sex of the owner -Can occasionally determine race

RFLPs

-Restriction enzymes are used to RFLPs in the DNA helix -All humans have the same type of repeats -Typically, the restriction enzyme cuts DNA at very specific placed -Gel electrophoresis is used to sort the different lengths of DNA fragments

Uniqueness of RBCs

-Shape: biconcave disc, round and flat -No nucleas -Can change shape -Contains hemoglobin

Darkfield Microscopy

-Shows a light silhouette of an organism againsts a dark background. The light reaches the specimen from an angle with the help of an opaque disk -The specimen then appears lit up: against the dark background -Useful for very small living organisms

Blood falling from a wound only under the influence of gravity is referred to as a

Passive bloodstain

What does the LD50 of a substance refer to?

The amount of substance necessary to kill off half of the population

Fluorescence Miscroscopes

-Specimens are first stained woth fluorochromes and then viewed through a compounf microscope by using an ultraviolet light source -Used primarily in a diagnostic procedures called flourescent-antibody technique

Phase Contrast Microscope

-Splits a beam of light into 2 types of light, a direct and refracted and brings them together to form an image of the specimen -Allows detailed observations of internal structures.

Compound Light Microscope

-The most commo microscope -Two sets of lenses: ocular and objective -Optical system comprised of condenser, objective lens, eyepiece lens and illuminator

Transmission Elec. Microscope (TEM)

-Thin sections can be seen in transmission electron micrograph -Electrons pass directly through the specimen

Scanning Elec. Microscope

-Views of the surfaces by aiming a beam of electrons onto the specimen

Six critcal questions "posed" by a pathologists

-Who are you? -When did you become ill/hurt/die -Where did you get hurt/die -Did you die as a result of violence, natural causes or combo -Was it suicide, accidental, homicide, undetermined -Who killed you

White blood cells

-a part of the immune system and fights infection -circulate in the blood to be transported to an infection sight -when the number of WBCs in your blood increases it is a sign of an infection

Visualizing fingerprints for porous surfaces

-iodine fuming -ninhydrin -superglue fuming

Red Blood Cells

-most abundant cells in the blood -RBCs ac% of the blood -The % of blood made up of RBCs is frequently measured and is called the hematocrit. -The ratio of cells in normal blood is 600 RBCs for each white blood cell and 40 platelets

Blood chemistry

1. Blood rich in CO2 - pumped from the heart into the lungs through the pulmonart arteries 2. CO2 in the blood is exchanged for O2 in the lungs 3. Oxygen-rich blood - back to the heart through pulmonary veins 4. Oxygen-rich blood - pumped from the heart to the body through arteries 5. In the tissues, the arteries narrow to tiny capillaries where O2 int he blood is exchanged for CO2 6. The capilaries widen into the veins which carry CO2 blood back to the heart

What is true about forensic science?

1. Evidence provides info that can and should influence the beliefs of an observer aout a specific legal quesiton 2. Evidence must be relevant 3. Experts must employ the same level of intellectual rigor as experts in the relevant field

Autopsy

1. External examination 2. Internal examination 3. Removal of the brain 4. Weighting the Organs 5. Examination of the Stomach and GI Tract 6. Sample Collect 7. Return Organs to Body

Biome

A large community of plants and animals that occupy a habitat in the natural world

What is PCR

A technique that can produce many exact copies of segments of DNA

A protein is a biopolymer built by deocding the DNA and is composed of many ___ units connected in a chain

Amino acid

Hair growth phases

Anagen - initial phase where hair actively grows (up to 6 years) Catagen - transition between active and loss stage, slowed growth (up to several weeks) Telogen - final phase resulting in hair loss (up to 6 months)

Time of Death

Antemortem: prior to death Perimortem: about the time of death Postmortem: After death Postmortem interval: The time between the actual death and finding the body

What is the "Fruit of the Poisonus Tree Doctrine"?

Any evidence found through a illegal search also cannot be used to find other evidence

Blood in the arteries vs. Blood in the veins

Arteries: is oxygen-rich (from lungs) Veins: is oxygen-poor

Fly development

At warmer temps the rate of development is fast, at cool temps it slows down

The light given of by fireworks is an example of what?

Atomic emission

The Decay Stage of decompisition

Begins when the abdominal wall breaks, gasses escape and the carcass deflates

Back spatter

Blood directed back towards the source of energy or force that caused the spatter

The chief function of the liver system

Blood purification

Forward spatter

Blood which travels in the same direction as the source of energy or force which caused the spatter.

Morphology of Hair

Cuticle - scales on exterior of hair shaft Cortex - main body of shaft Medulla - either absent or contains 1/3 diameter of the shaft

How does burial impact the decay process

Burial can slow the decay process

Chemical formula of ethonal (the "alcohol" in alcoholic beverages)

CH3CH2OH

What is the document that certifies that a piece of evidence has been handled properly from discovery to analysis to allow admission into court?

Chain of custody form

Secondary explosives

Compounds that are relatively stable to heat, shock, eletrical discharge, and friction and usually require much more energy to detonate

Primary explosives

Compounds that are sensitive to heat, flame, shock or friction and typically detonate quickly.

AFIS

Computerized system for storing and retrieving finderprint records

The main advantage and difference of the Daubert Standard over the Frye Standard is that

Daubert allows new types of scientific evidence to be used in court faster

Post Decay Stage

Day 10-25 In dry habitats, remains are skin cartilage, and bones. In wet habitats, wet material in the soil under the remains -Large maggots are leaving or have left

Dry Stage

Day 25+ Mainly bones and hair remain. Odor is primarily that of normal soil and litter. Can last several months to years -Beetles move in and other insects with the ability to digest keratin

Fresh Stage

Days 1-2 Commencing at death, ends when bloating is first evident. Breakdown of protein and carbohydrates into simpler compounds -Blowflies detect cadavar and lay eggs

Bloated Stage

Days 2-6 Putrefaction begins. Gasses produced by anaerobic bacteria inflate the adbomen -Flesh flies appear; small maggots are feeding

Under what circumstances can illegally obtained evidence generally be used in court?

During post-trial sentencing

The process of spectroscopy in which an electron moved from a higher energt state to a lower energy state

Emission

With regard to skeletized human remains, which of the following may be used to estimate the age of an individual at the time of his/her death?

Epiphyseal Union

Hemoglobin

Hemoglobin is a protein containing heme group.

A precipitin test is used primarily to identify

If the blood found is human

The police are not required to obtain a search warrant if they are

In the process of a legal arrest

Evidence that can be associated with a particular source with an extremely high degree of probability is said to possess

Individual characteristics

Transfer bloodstain

Is created when a wet, bloody surface comes in contact with another surface

Atoms of a given element with different numbers of neutrons but the same number of protons

Isotopes

How did the Frye decision of 1923 impact the admissibility of forensic evidence?

It established the minimum standards for admissibility of scientific evidence

Hair can most often be characterized as originating from an animaly by examining

Its cuticle (scale) structure

Where in the body is most of ingested alcohol completely oxidized?

Liver

The process by which the blood in a body settles to the lowest point after death

Livor mortis

In mass spectrometry, moleculels with charges (ions) are deflected accordig to their mass by a what?

Magnetic field

A channel in the center of the hair shaft is known as the

Medulla

Cyanide is classified in toxicology as a what?

Metabolic poison

Rigor Mortis

Muscle fibers become cross linked, muscles stiffen. First noticed 2-4 hr pm. Remains 12-24 hrs.

Where are the chromosomes located in the body?

Nucleus

The fluid portion of blood as it is removed from someone that accounts for approximately 55% of blood is known as the

Plasma

What is the frequency of occurance of an event

Probability

What structure of the pelvis can determine the gender if its owner?

Pubic arch

In the case of Mincy v. Arizona, with respect to the collection of evidence, the main importance was

Sets limits on the collection of evidence as to the reasonable extent and duration of an emergency

Proxy indicators

Small amounts of identifiable material from an ecosystem that can indicate with relatively high accuracy

Satelitte Spatter

Small droplets of blood that are distruted around a drop or pool of blood as a result of the blood impacting the target surface

What is an example of identification analysis?

Spectrophotometric determination that a sample is cocaine

What microscope has the ability to examine larger objects in 3D readily?

Stereoscopic

Angle of impact

The acute angle formed between the direction of a blood drop and the plane of the surface that it strikes

Algor Mortis

The change in body temperature

In gas chromatography using a long glass tue to separate components of a complex mixture, which of the following is the stationary phase?

The glass tube

Locard's Exchange Principle

The most basic concept of Forensic Science: -Criminal in contact with an object or person, a cross transfer of evidence occurs -Examples;dust, biological samples, fingerprints, chemical residues

Forensic taphonomy

The movement of the body after death

PMI

The time interval since death

What is the best definition of forensic science?

The use of scientific methods to help answer legal problems

As the angle of impact decreases

The width of the blood stain increases and vice versa

Nucleic Acids

Three "building blocks" linked through condensation reactions to form polymers

Blood type

Type A: Only the A protein is present/ B antibody is present Type B: Only the B protein is present/ A antiody is present Type AB: Both proteins are present/ Neither A nor B antobies present Type O: Neither protein is present/Both A and B antobodies are present

The Principle of Individuality means that

Two objects may be indistiguishable but they are never identical

Luminol Test

Used for Blood ID -Very sensitive -Detects unseen samples and patterns -Does not interfere with later DNA testing

Immunoassy

a technique utilizing antibodies to bind specifically to targeted substances in a specimen in order to identify their presence

Osteology

study of skeletal remains -Human bones vs. animal bones -Macroscopic differences -Radiology -measurement -Miscroscopic differences