Final exam study guide Flashcards
Individual evidence
Links to one unique source human/object
Locard’s principle
“Every contact leaves a trace”
And also known as trace evidence.
Physical evidence
Tangible items
Probative value
The ability to prove something that is material to a crime
Physical evidence examples
Fibers, fingerprints, glass, hair, Blood
Class evidence
Can be linked to a group of people or objects.
Primary/Secondary crime scene
Primary: the original location of CRIME or evidence.
Secondary: an alternative location where additional information may be found.
Chain of Custody
The movement and location of physical evidence from the time it is obtained until the time it is presented in court.
Packaging Evidence (Blood evidence, Fingerprints)
Each item must be collected in separate container or package and label it.
Material must not be put into an airtight bag
Presumptive test
Is an analysis of a sample which establishes either: the sample is definitely not a certain substance or the sample is probably a substance.
Confirmatory Test
Can help determine what the substance is: Limitations is that it could be wrong.
BAC
Blood alcohol content:
BAC(girl)=(0.085) ( oz)(%) / Weight
BAC(boy)=(0.071)
Find the BAC of a women who drinks three 5-ounce glasses of wine. Her weight is 135 pounds and the wince is 9% alcohol.
BAC=(0.085)(15)(9)/135
BAC=0.085 (answer)
What is the proof of a type of liquor that causes a 142 pound man to have a BAC of 0.075 after consuming six one-ounce shots?
0.075=(0.071)(6)(%) / 142
10.65=0.426X
X=25%
Double 25 and it equals 50 proof(the answer)
Positive control
Known blood will cause the color to appear (solutions are working)
Negative control
Absence of blood - no appearance of color-showing no contamination
Preciptin Test
Helps determine if it’s Human blood or animal blood
Drug Metabolism
Is the removal of drugs from the body once they have preferred their function.
Enzymes
Less active enzymes can lead to drug toxicity
Alcohol
Ethanol
Alcohol is absorbed
- 20% in stomach and 80% small intestines
- Average rate of removal is 0.015 percent per hour
- Most of metabolism takes place on the liver
Why is Alcohol easily absorbed?
Due to it’s ease of dissolution in water
Alcohol is hydrophilic (attracted to water) muscles have water and fat doesn’t which is the reason why women have a higher BCC rate than men because men have more muscles.
How does breathalyzer work?
Determines ethanol in breath, since alcohol is excreted in sweat, urine, and breath.
What class is Narcotic placed in? And give an example of one?
Cocaine, Heroin
(Morphines)
Class A
What class is stimulant? Example?
-Increases brain activity
-caffeine, nicotine,ecstasy
Class C
What class is hallucinogen, example?
LSD, PCP
Class B
What class is depressants? Example
Class B
Amphetamines
Opiod
Barbiturates
What is chromatography?
A technique to separate mixtures into their components
Retention factor: Rf
Rf= distance component moves/ distance solvent moves
What is a stationary phase?
Paper
What is the mobile phase?
liquid solvent
Development system
Making invisible spots visible
Chronic exposure
Large amounts taken over a period of time
Acute toxicity
One dose taken/given that is large enough to cause death
LD50
Is the amount of toxin that will kill half of the test population
Unit-Mg/kg
2.2lb=1kg
Mg poison / kg body mass
1mg/kg x 82kg= 82 mg lethal dose
Passive bloodstain
Flow pattern-from a moving surface
Projected bloodstain
Low velocity- is a big spatter(large bloodstain)
(Gunshot wound)
High velocity- tiny spatters
Some form of energy has been transferred to a blood source
Transfer bloodstain
Example: a shoe print
An object with blood on it comes an contact with an object or surface that doesn’t have blood on it
Rh factor
Rh+ means that the factor is present
Rh- means that the factor is absent
Antigens and Antibodies
Each blood type has antibodies to protect against the wrong type of antigen
Type A has A antigen
Type B has B antigen
Antigen surround the red blood cell
Blood components
Plasma- the liquid part of fhe blood
90% water
10%metabolites(waste, salts, ions, proteins)
Cells-erythrocytes,leukocyte, platelets
Latent fingerprint
Latent prints are impressions produced by the friction ridges, om human fingers, palms, and soles of the feet. Examiners analyze and compare latent prints to known prints of individuals in an effort to make identification or exclusions
Patent fingerprints
Patent fingerprints, Can be made by ink, grease , dirt , this type of fingerprint is easily visible to the human eye.
Plastic fingerprints
Are three dimensional impressions and can be made by pressing your finger in fresh paint, wax or soap.
