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Forensics test
Forensics-Blood, DNA, Toxicology
| Term | Definition |
|---|---|
| blood typing | Class-evidence |
| Blood-spatter | recreate crime scene |
| DNA profiling | individual evidence |
| how much blood is in the human body | 5 liters |
| red blood cells | carry gases (oxygen, carbon dioxide) |
| hemoglobin | iron containing protein that binds to O2- gives blood the red color |
| white blood cells | fights disease and foreign invaders |
| Ethyl alcohol | breaks open cells, exposes hemoglobin |
| phenolphthalein ( Kastle-Myer reagent) | reducing agent; turns pink when oxidized |
| Hydrogen peroxide | reacts with hemoglobin- if blood is present, swab will turn pink |
| Anti-bodies | Y shaped proteins secreted by WBC's which aid in immune response |
| antigens | foreign substance or cell that reacts to antibodies |
| Agglutination | clumping of blood cells |
| Polymorphic proteins | Group-specific components and haptoglobins |
| light source | investigators will first examine the crime scene to look for areas that may contain blood. they may use a high-intensity light or UV lights to help them find traces of blood as well as other bodily fluids that are not visible under normal lighting. |
| Blood reagents tests | these tests, referred to as presumptive tests, are used to detect blood at crime scenes based upon the properties of hemoglobin in the blood |
| Hemastick | a strip that has been coated with tetramethylbenzidine and will produce a green or blue-green color with the presence of hemoglobin. helps with finding blood in urine |
| Luminol/ blue star | this chemical is used by crime scene investigators to locate traces of blood, even if it has been cleaned or removed |
| PHYSICAL PROPERTIES OF BLOOD | NEW SECTION |
| 1. Cohesion | blood sticks together as it falls |
| 2. Gravity | pulls blood downward |
| 3. Surface tension | blood drops that fall on a flat surface have a curved surface |
| 4. Satellites | small secondary droplets |
| 6 PATTERNS OF BLOOD SPATTER | NEW SECTION |
| 1. Passive fall (90 degree angle to floor) | circular drops with secondary satellites |
| 2. Arterial | Spurts or gushes |
| 3. Splashes | Shows position of Victim |
| 4. Smears | Bleeding victim touching walls or furniture |
| 5. Blood trails | Victim moving from one place to another |
| 6. Blood pools | Victim bleeds heavily |
| OTHER BLOOD PATTERNS | NEW SECTION |
| Cast off pattern | Blood from a moving object coated in blood ( pipe, knife) |
| Fine-mist spatter | High-velocity impact (Gunshot) |
| Void | Empty space; victim/attacker/object moved after attack |
| BLOOD SPATTER TYPES | NEW SECTION |
| 1. High Velocity | Gunshot wounds |
| 2. Medium Velocity | Beating, Stabbing |
| 3. Low Velocity | Blunt object impact |
| Lines of convergence | Determines source of blood (Point of origin), Draw straight lines down long axis of blood spatter |
| ***DNA FINGERPRINTING NOTES*** | ***NEW NOTES*** |
| Purpose of DNA fingerprinting | Determines identity (match tissue samples), Establish Paternity |
| Individual evidence | Identify a single person |
| Trace evidence | Small amount left at crime scene |
| DNA | Stores genetic information, DeoxyriboNucleic Acid, found in nucleus of cells |
| Exons | Encoded DNA-1.5% of DNA |
| Introns | Uncoded DNA-98.5% of DNA |
| Mitochondrial DNA (mtDNA) | inherited ONLY from mother |
| Chromosomes | Each person has 46 Chromosomes, 23 pairs- 1 set from mom, 1 set from dad |
| Genes | segment of DNA that contains info to produce a protein |
| Allele | alternate forms of a gene-inherit 1 allele from mom, 1 allele from dad |
| STEPS OF DNA FINGERPRINTING | NEW SECTION |
| 1. Extraction | Take DNA out of cells |
| 2. Amplification | Make copies of DNA- Use PCR (polymerase chain reaction) |
| 3. Electrophoresis | DNA pieces separated within an agarose gel or capillary tube |
| PCR Machine | Amplifies (makes copies of) DNA |
| Polymorphisms | Differences in DNA sequences (0.1%) |
| RFLP Analysis | older method of DNA testing, requires quarter-sized DNA samples |
| STR ( Short Tandem Repeat) | Very small or degraded DNA samples, Most current technology in use |
| mtDNA | Trace maternal relatives, Evidence: hair, old bones/teeth |
| Y-STR | Trace paternal relatives, Y-chromosome analysis |
| CODIS | COmbined DNA Index System |
| ***GEL ELECTROPHORESIS NOTES*** | ***NEW NOTES*** |
| Gel Electrophoresis | Method of separating molecules within an electric field based on the SIZE and CHARGE of DNA fragments |
| Gel | Matrix used to separate DNA- usually agarose |
| Buffer | Salt solution that conducts electricity |
| Well | Slots in the gel where samples are loaded |
| Small DNA | Moves faster |
| Larger DNA | Moves slower |
| ***TOXICOLOGY NOTES*** | ***NEW NOTES*** |
| What is Poison? | Anything can be a poison, A poison is any substance that, when taken in sufficient quantities, causes a harmful or deadly reaction |
| Intoxicant | Requires that you ingest a rather large amount |
| Poison | Only requires you to ingest a small amount |
| Toxicology | Toxicology deals with drugs, poisons, and other toxic substances and how these substances alter or harm living organisms |
| Forensic Toxicology/Forensic Toxicologist | Finds a toxin and figures out what would happen to a person that ingested/contacted it |
| Toxicologist | Asses the state of inebriation an automobile or industrial accident victim, determines whether someone died from poison or from a natural cause, Assesses whether drugs played a role in a criminals actions |
| Biotransformation | when one chemical changes into another in the body, also called metabolism |
| Metabolites | The new chemicals that happen when the body tries to break down/get rid of a toxin |
| Metallic elements | also cause disease and death |
| How does forensic toxicology help solve crimes? | Helps solves crimes by detecting and identifying drugs and poisons |
| What are the two general types of illegal psychoactive drugs that exist? | Depressants and stimulants |
| What do psychoactive drugs change or mimic in the human body? | they change or mimic Neurotransmitters |
| What are some of the effects depressants have can have upon an individual? | Drowsy, relaxed, sad, pain prevention |
| What happened to the levels of drug-related arrests in the past 30 years? | They have tripled |
| Where are psychoactive drugs broken down in the body? | Liner or target region |
| Outline where in the body Forensic toxicologists will likely find psychoactive drugs or their breakdown products? | Blood, Urine, or CNS |
| Sequence that psychoactive drugs travel through in the human body | Blood, CNS, Liver, Kidneys, Urine |
| NEGATIVE SIDE EFFECTS OF PSYCHOACTIVE DRUGS | NEW SECTION |
| Cocaine | Can cause confusion, Insomnia, and impotence |
| Amphetamines | Inflammation of heart lining and skin abscesses |
| Opiates | Disrupts blood flow and increased chance of infection |
| Marijuana | Severely interferes with one's ability to operate a motor vehicle |
Created by:
carlyrose22
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