Biological Evidence Full Review

Forensic science is the application of science in a legal environment.

The aim of a forensic scientist is to objectively examine the evidence in a scientific manner and present the results clearly.

The role of a forensic serologist is to analyze biological evidence.

<p>Some types of samples routinely analyzed by a forensic serologist include blood, semen, saliva, and other bodily fluids.</p> Signup and view all the answers

<p>Measures needed to prevent contamination of evidence include using proper protective equipment, following strict protocols, and maintaining a clean and controlled laboratory environment.</p> Signup and view all the answers

<p>Karl Landsteiner</p> Signup and view all the answers

<p>Ludwig Teichman</p> Signup and view all the answers

<p>Karl Landsteiner</p> Signup and view all the answers

<p>Karl Landsteiner</p> Signup and view all the answers

<p>Kary Banks Mullis</p> Signup and view all the answers

<p>Every contact leaves a trace</p> Signup and view all the answers

<p>Forensic Pathology</p> Signup and view all the answers

<p>Investigation and analysis of biological evidence</p> Signup and view all the answers

<p>Trace Evidence</p> Signup and view all the answers

<p>Bi-directional transfer</p> Signup and view all the answers

<p>Colder temperatures</p> Signup and view all the answers

<p>Adipocere</p> Signup and view all the answers

<p>Within one to 3 years</p> Signup and view all the answers

<p>Stomach contents</p> Signup and view all the answers

<p>Decompose them</p> Signup and view all the answers

<p>Adipocere formation</p> Signup and view all the answers

<p>None of the above</p> Signup and view all the answers

<p>Blisters</p> Signup and view all the answers

<p>Decomposition</p> Signup and view all the answers

<p>Colder temperatures</p> Signup and view all the answers

<p>The decomposition process is generally slowed due to colder temperatures.</p> Signup and view all the answers

<p>Adipocere is a waxy covering that can preserve a body.</p> Signup and view all the answers

<p>Within one to 3 years, all soft tissues will have disappeared leaving only bones.</p> Signup and view all the answers

<p>The term used is decomposition.</p> Signup and view all the answers

<p>The pressure can cause fluid-filled blisters to appear on the skin.</p> Signup and view all the answers

<p>Household bleach diluted 1:10</p> Signup and view all the answers

<p>All of the above</p> Signup and view all the answers

<p>Eye protection</p> Signup and view all the answers

<p>Shoes that completely cover and protect the foot</p> Signup and view all the answers

<p>When there is potential for contamination or transfer from airborne biohazards</p> Signup and view all the answers

<p>Injection</p> Signup and view all the answers

<p>Infection control</p> Signup and view all the answers

<p>Precautions taken to avoid direct contact with potentially infectious materials</p> Signup and view all the answers

<p>Using regular hand washing</p> Signup and view all the answers

<p>Exposure to biological hazards</p> Signup and view all the answers

<p>They can be easily understood by investigators</p> Signup and view all the answers

<p>To destroy its evidentiary value</p> Signup and view all the answers

<p>The type of weapon used</p> Signup and view all the answers

<p>All of the above</p> Signup and view all the answers

<p>They are the same as those at any other crime scene</p> Signup and view all the answers

<p>Samples are susceptible to damage, degradation, and contamination. Improper handling, collection, packaging, and storage can compromise the integrity of a sample.</p> Signup and view all the answers

<p>The objectives of this module are to familiarize students with the types of samples analyzed by forensic serologists, the general processes of crime scene processing, and crime scene investigation in relation to obtaining biological evidence.</p> Signup and view all the answers

<p>Proper handling, collection, and storage of biological evidence is important to ensure optimum results and preserve the integrity of the sample.</p> Signup and view all the answers

<p>Forensic serologists routinely analyze biological samples such as blood, cells, and tissues.</p> Signup and view all the answers

<p>Improper handling, collection, packaging, and storage can easily compromise the integrity of a DNA sample.</p> Signup and view all the answers

<p>Knowledge of forensic analysis</p> Signup and view all the answers

<p>Blood</p> Signup and view all the answers

<p>DNA samples</p> Signup and view all the answers

<p>Amido Black</p> Signup and view all the answers

<p>Blue</p> Signup and view all the answers

<p>Multi-colored surfaces</p> Signup and view all the answers

<p>Bloody footwear impressions</p> Signup and view all the answers

<p>Size of the light source</p> Signup and view all the answers

<p>To enhance the visualization of bloodstains and other body fluids</p> Signup and view all the answers

<p>To identify areas of suspected blood staining</p> Signup and view all the answers

<p>Placing it in a plastic bag</p> Signup and view all the answers

<p>Packing it in a paper bag or envelope</p> Signup and view all the answers

<p>Less than two hours</p> Signup and view all the answers

<p>Packing it in a paper bag or envelope</p> Signup and view all the answers

<p>Leak-proof containers</p> Signup and view all the answers

<p>The collecting person's initials</p> Signup and view all the answers

<p>Vaginal, oral, and rectal swabs</p> Signup and view all the answers

<p>To prevent critical evidence from being destroyed or lost</p> Signup and view all the answers

<p>Victim's underwear</p> Signup and view all the answers

<p>By using side lighting or special light sources</p> Signup and view all the answers

<p>To preserve the integrity of the evidence for future examination</p> Signup and view all the answers

<p>To determine the source of bloodstains leading away from the scene</p> Signup and view all the answers

<p>Paper containers</p> Signup and view all the answers

<p>Blood, hair, and saliva samples</p> Signup and view all the answers

<p>Plastic containers can contaminate the evidence</p> Signup and view all the answers

<p>Exposure to excessive heat</p> Signup and view all the answers

<p>4°C</p> Signup and view all the answers

<p>Final disposition of the evidence</p> Signup and view all the answers

<p>To record evidence recovery, handling, and analysis</p> Signup and view all the answers

<p><a href="http://www.crime-scene-investigator.net/blood.html">http://www.crime-scene-investigator.net/blood.html</a></p> Signup and view all the answers

<p>Freezing the swabs</p> Signup and view all the answers

<p>10ml</p> Signup and view all the answers

<p>Collecting a swab from a wet biological material</p> Signup and view all the answers

<p>Using a sterile, moistened cotton swab to swab the clippings</p> Signup and view all the answers

<p>Freezing the samples and transporting them on ice</p> Signup and view all the answers

<p>Some commonly used techniques to find blood in forensic casework include luminol testing, phenolphthalein testing, and alternate light sources.</p> Signup and view all the answers

<p>False positive and false negative tests can have serious consequences in forensic biology as they can lead to incorrect conclusions and potentially wrongful convictions.</p> Signup and view all the answers

<p>Preliminary tests are quick and easy to perform, but they are not specific to blood and can produce false positives. Confirmatory tests are more specific to blood and provide conclusive results.</p> Signup and view all the answers

<p>Preliminary tests for blood rely on the detection of a substance called hemoglobin, which is found in red blood cells. Screening tests use chemical reactions to detect the presence of blood proteins.</p> Signup and view all the answers

<p>Specificity refers to the ability of a test to correctly identify the presence of a specific substance, such as blood. Sensitivity refers to the ability of a test to correctly identify the absence of a specific substance, such as blood.</p> Signup and view all the answers

<p>Evidence from different sources such as suspect, victim, and scene, should be examined in separate areas/rooms to avoid cross-contamination of trace materials (hairs, fibers, etc). Once an item of evidence is selected for examination, the evidence bag is opened carefully in a manner that preserves the original seal and signature. The contents are carefully removed onto the paper, and the bag is checked to recover any trace evidence that may be lost in the packaging. While making notes at each step, the item is sketched and carefully searched; obvious debris and potential evidence is recovered, recorded and packaged; fibers and hairs are mounted on glass slides and other trace evidence is packaged and submitted to the appropriate section for analysis (pieces of glass or paint may be submitted to the appropriate section (chemistry, criminalistics) for analysis.</p> Signup and view all the answers

<p>Notes can reflect the characteristics of the item such as color, manufacturer, size, any tears/damage, stains, etc. which makes it easy to identify in court.</p> Signup and view all the answers

<p>Presumptive tests are carried out on suspect stains. If stains present on the clothing are negative, remainder of item needs to be swabbed and tested as well since not all stains are visible to the naked eye. Areas of stain that test positive with presumptive tests are selected for confirmatory tests and DNA analysis; Genetic differences between a suspect stain and a reference sample taken from the possible source allows that source to be positively eliminated (this source could be a victim or an assailant).</p> Signup and view all the answers

<p>Arteries</p> Signup and view all the answers

<p>The type of blood vessel</p> Signup and view all the answers

<p>Veins</p> Signup and view all the answers

<p>Arterial spurt</p> Signup and view all the answers

<p>Veins</p> Signup and view all the answers

<p>Infrared lighting</p> Signup and view all the answers

<p>Perform a visual exam</p> Signup and view all the answers

<p>Yellowish-greenish</p> Signup and view all the answers

<p>To locate and differentiate between blood and other similarly colored stains</p> Signup and view all the answers

<p>Luminol</p> Signup and view all the answers

<p>Add a drop of reagent to stain extract, add a drop of hydrogen peroxide, observe color change</p> Signup and view all the answers

<p>Phenolpthalein</p> Signup and view all the answers

<p>They are a one-step process</p> Signup and view all the answers

<p>Difficult stain transfer</p> Signup and view all the answers

<p>All of the above</p> Signup and view all the answers

<p>Microchemical test</p> Signup and view all the answers

<p>It can be used on a range of stain types</p> Signup and view all the answers

<p>They are disrupted by dirt and particulate matter</p> Signup and view all the answers

<p>The need to find intact cells within the stain</p> Signup and view all the answers

<p>All of the above</p> Signup and view all the answers

<p>Spectroscopy</p> Signup and view all the answers

<p>Human hemoglobin in a sample</p> Signup and view all the answers

<p>It reacts positively with ferret blood</p> Signup and view all the answers

<p>Antibody-antigen reaction</p> Signup and view all the answers

<p>They may include a disclaimer in the lab report</p> Signup and view all the answers

<p>There are several tools used in laboratories to aid in locating stains of interest, including alternate light sources (ALS), which can help visualize stains that may not be visible to the naked eye, and microscopes, which can be used to examine stained areas in more detail.</p> Signup and view all the answers

<p>Commonly used techniques to locate and test semen, saliva, and other biological fluids in forensic casework include visual examination under alternate light sources, use of chemical reagents for presumptive testing, and microscopic examination for confirmatory testing.</p> Signup and view all the answers

<p>Multi-section cases can present challenges related to the coordination of evidence analysis across different sections or laboratories, ensuring the integrity of the evidence during transportation and storage, and maintaining effective communication among the involved parties.</p> Signup and view all the answers

<p>PSA</p> Signup and view all the answers

<p>30,000 kD</p> Signup and view all the answers

<p>ELISA</p> Signup and view all the answers

<p>Seratec PSA Semiquant</p> Signup and view all the answers

<p>P30 test</p> Signup and view all the answers

<p>1 to 8 hours</p> Signup and view all the answers

<p>Up to 26 hours</p> Signup and view all the answers

<p>Up to 7 days</p> Signup and view all the answers

<p>1 day or less after the incident</p> Signup and view all the answers

<p>5 days or more before the incident</p> Signup and view all the answers

<p>Sublingual, submandibular, and parotid glands</p> Signup and view all the answers

<p>All of the above</p> Signup and view all the answers

<p>Parotid gland</p> Signup and view all the answers

<p>Anagen phase</p> Signup and view all the answers

<p>Human hairs have a continuous diameter shaft, while animal hairs have an inconsistent diameter shaft</p> Signup and view all the answers

<p>Up to 100 hairs</p> Signup and view all the answers

<p>Phadebas tablets</p> Signup and view all the answers

<p>To produce a clear area on the gel after staining with iodine solution</p> Signup and view all the answers

<p>When saliva is used as a lubricant in the assault</p> Signup and view all the answers

<p>Litmus paper test</p> Signup and view all the answers

<p>Detection of urobilinogen</p> Signup and view all the answers

<p>To determine the presence of glycogenated cells</p> Signup and view all the answers

<p>Bloodstains on clothing</p> Signup and view all the answers

<p>Remove trace evidence</p> Signup and view all the answers

<p>Wear latent gloves</p> Signup and view all the answers

<p>Antigen antibody reactions, electrophoresis, determination of blood group based on red cell antigens, determination of ABO blood type, secreter status, biochemical markers</p> Signup and view all the answers

<p>Knowledge and understanding of these techniques may be important in analyzing old or unsolved cases</p> Signup and view all the answers

<p>Advantages: biochemical markers can provide additional information about an individual's characteristics or history. Disadvantages: biochemical markers can be influenced by various factors and may not always provide conclusive evidence</p> Signup and view all the answers

<p>Post-conviction analysis may involve re-examining evidence using these specialized techniques to confirm or challenge previous findings</p> Signup and view all the answers

<p>These techniques are still routinely used in less developed countries where adequate funding for DNA analysis is not available</p> Signup and view all the answers

<p>Ouchterlony double diffusion</p> Signup and view all the answers

<p>Immunodiffusion and subsequent precipitation</p> Signup and view all the answers

<p>Specificity</p> Signup and view all the answers

<p>DNA testing</p> Signup and view all the answers

<p>All of the above</p> Signup and view all the answers

<p>OO</p> Signup and view all the answers

<p>6</p> Signup and view all the answers

<p>H antigen</p> Signup and view all the answers

<p>80%</p> Signup and view all the answers

<p>Anti A and Anti B</p> Signup and view all the answers

<p>Capillary electrophoresis</p> Signup and view all the answers

<p>The amino acid composition of the protein</p> Signup and view all the answers

<p>To determine the presence of the proteins</p> Signup and view all the answers

<p>Subtle variations in protein charge</p> Signup and view all the answers

<p>To determine the size of DNA molecules</p> Signup and view all the answers

<p>To determine the origin of biological stains and fluids</p> Signup and view all the answers

<p>Dependent on the distribution of other markers</p> Signup and view all the answers

<p>The probability of a bloodstain having a specific combination of markers</p> Signup and view all the answers

<p>The smaller the frequency of occurrence in the population</p> Signup and view all the answers

<p>The distribution can vary significantly between regional populations</p> Signup and view all the answers

<p>It is a glycoprotein found in the alpha-2 globulin fraction of serum proteins</p> Signup and view all the answers

<p>Erythrocyte acid phosphatases can be found in the cytoplasm of other tissues</p> Signup and view all the answers

<p>Many of the genetic factors found in blood can also be found in other body fluids</p> Signup and view all the answers

<p>Protein markers in wet samples degrade through the action of microbiological processes and endogenous enzymes</p> Signup and view all the answers

<p>Drying of samples and storage under refrigerated or freezing conditions significantly slow degradation processes</p> Signup and view all the answers

<p>Ge protein is also known as vitamin D binding protein; a glycoprotein in the alpha-2 globulin fraction of serum proteins, produced by the liver.</p> Signup and view all the answers

<p>Semen</p> Signup and view all the answers

<p>Some protein markers</p> Signup and view all the answers

<p>Saliva</p> Signup and view all the answers

<p>Hair, tooth pulp, and inner ear fluid</p> Signup and view all the answers

<p>The basic characteristics of blood spatter patterns include the size and shape of the blood droplets, the distribution and directionality of the spatter, the presence of satellite spatter, and the presence of voids or gaps in the pattern.</p> Signup and view all the answers

<p>The factors that cause blood spatter formation include the force or velocity applied to the blood, the angle at which the blood impacts a surface, the distance between the source of the blood and the surface, and the type of surface the blood impacts.</p> Signup and view all the answers

<p>The limitations of blood spatter interpretation include the variability of blood behavior, the potential for contamination or alteration of the spatter pattern, the lack of standardized guidelines for interpretation, and the need for expert analysis and training to accurately interpret the patterns.</p> Signup and view all the answers

<p>Artery</p> Signup and view all the answers

<p>Deliver nutrients and oxygen</p> Signup and view all the answers

<p>Artery</p> Signup and view all the answers

<p>Supply each region of the body with freshly oxygenated blood</p> Signup and view all the answers

<p>Arteries have strong elastic walls, while capillaries have fragile walls</p> Signup and view all the answers

<p>High velocity spatter</p> Signup and view all the answers

<p>90°</p> Signup and view all the answers

<p>13-21 mm</p> Signup and view all the answers

<p>Glass</p> Signup and view all the answers

<p>Type of amino acids present</p> Signup and view all the answers

<p>Blowback or back spatter</p> Signup and view all the answers

<p>1-3 mm</p> Signup and view all the answers

<p>Projected stains</p> Signup and view all the answers

<p>Splashed blood</p> Signup and view all the answers

<p>Expirated blood</p> Signup and view all the answers

<p>Valves prevent the backflow of blood in veins</p> Signup and view all the answers

<p>Blue</p> Signup and view all the answers

<p>Platelet activation</p> Signup and view all the answers

<p>25 feet/second</p> Signup and view all the answers

<p>Viscosity and specific gravity</p> Signup and view all the answers

<p>Skeletonized bloodstain</p> Signup and view all the answers

<p>Drag pattern</p> Signup and view all the answers

<p>Expirated stain</p> Signup and view all the answers

<p>All of the above</p> Signup and view all the answers

<p>Photography</p> Signup and view all the answers

<p>Blood transfer pattern is produced when a wet bloody object comes into contact with another object or surface, creating a pattern that mirrors the original surface.</p> Signup and view all the answers

<p>Altered stains are stains that have been modified or changed in some way. Examples include skeletonized bloodstains and clots of blood.</p> Signup and view all the answers

<p>Wet bloodstains are susceptible to smearing, smudging, and wiping by the assailant and victim.</p> Signup and view all the answers

<p>The types of blood spatter that can be found on clothing include transfer, flow patterns, saturation stains, and drips.</p> Signup and view all the answers

<p>When recording bloodstains and spatter, it is important to note the form, color, and size of the stains, the direction of splash, and the estimated height of fall.</p> Signup and view all the answers

<p>The basic principles of DNA analysis include extracting DNA from a sample, quantitating the amount of DNA present, amplifying specific regions of the DNA through PCR, and separating the amplified DNA fragments through electrophoresis.</p> Signup and view all the answers

<p>CODIS (Combined DNA Index System) is a database used in forensic DNA analysis to store DNA profiles from convicted offenders, crime scene evidence, and missing persons. It allows for comparisons and potential matches between different DNA profiles.</p> Signup and view all the answers

<p>mDNA (mitochondrial DNA) testing analyzes the DNA found in the mitochondria, which is inherited maternally. Y-STR (Y-chromosomal short tandem repeat) testing analyzes the DNA found on the Y-chromosome, which is inherited paternally.</p> Signup and view all the answers

<p>DNA</p> Signup and view all the answers

<p>Purines and pyrimidines</p> Signup and view all the answers

<p>Two</p> Signup and view all the answers

<p>Gel electrophoresis</p> Signup and view all the answers

<p>Restriction Fragment Length Polymorphism</p> Signup and view all the answers

<p>To analyze DNA variations</p> Signup and view all the answers

<p>Organic extraction</p> Signup and view all the answers

<p>DNA IQTM extraction</p> Signup and view all the answers

<p>Chelex extraction</p> Signup and view all the answers

<p>VNTR analysis</p> Signup and view all the answers

<p>STR testing</p> Signup and view all the answers

<p>STR testing</p> Signup and view all the answers

<p>Real-time PCR</p> Signup and view all the answers

<p>To make many copies of the DNA</p> Signup and view all the answers

<p>Denaturation, primer annealing, elongation</p> Signup and view all the answers

<p>To heat and cool the DNA sample</p> Signup and view all the answers

<p>Capillary electrophoresis</p> Signup and view all the answers

<p>To detect the DNA fragments during electrophoresis</p> Signup and view all the answers

<p>To collect data on the movement of DNA fragments</p> Signup and view all the answers

<p>Applied Biosystems</p> Signup and view all the answers

<p>Real-time PCR is used to determine the amount of DNA in a sample based on the fluorescence emitted during the polymerase chain reaction process. The quicker the fluorescence is detected, the more DNA is present in the sample.</p> Signup and view all the answers

<p>The three steps of the PCR process are denaturation, primer annealing, and elongation. During denaturation, the double stranded DNA molecule dissociates and becomes single stranded. Primer annealing involves attaching primers, which are short segments of DNA specific to the target sequence, to the single stranded DNA. Elongation is catalyzed by DNA polymerase and involves the addition of free nucleotides to extend the target sequence from the primers.</p> Signup and view all the answers

<p>Capillary electrophoresis is used to separate DNA fragments based on their size. The fragments, carrying fluorescent dye tags on the primers, migrate through a capillary under the influence of a charged field. The fragments are then detected and analyzed based on their migration time, which can be related to the base pair size of the fragment and the corresponding allele.</p> Signup and view all the answers

<p>It is beneficial in situations where there is limited amount of male DNA present in a sample</p> Signup and view all the answers

<p>It is less prone to degradation than nuclear DNA</p> Signup and view all the answers

<p>To perform DNA analysis on samples from convicted offenders and forensic casework</p> Signup and view all the answers

<p>To reduce the time required for a DNA analyst to perform extractions</p> Signup and view all the answers

<p>To perform DNA analysis on samples from convicted offenders and forensic casework</p> Signup and view all the answers

<p>An expert witness is summoned to provide opinion or expert evidence based on their expertise during a trial.</p> Signup and view all the answers

<p>Knowledge of the US criminal justice system, pre-trial preparation, and focused testimony are important for an expert witness to competently handle direct and cross-examination.</p> Signup and view all the answers

<p>The objectives of this module are to understand the basic principles of the US legal system, the basic processes of courtroom testimony, and the basic principles of effective courtroom presentation.</p> Signup and view all the answers

<p>Admit to making a mistake if you make one</p> Signup and view all the answers

<p>Say 'I don't know' or 'I was wrong' if applicable</p> Signup and view all the answers

<p>Admit to making the mistake</p> Signup and view all the answers

<p>Wear conservative clothing to convey professionalism</p> Signup and view all the answers

<p>Adopt a professional demeanor without appearing overly confident</p> Signup and view all the answers

<p>Say 'I don't know' or 'I was wrong'</p> Signup and view all the answers

<p>Admit to making the mistake</p> Signup and view all the answers

<p>Wear conservative clothing to convey professionalism</p> Signup and view all the answers

<p>Adopt a professional demeanor without appearing overly confident</p> Signup and view all the answers

<p>Say 'I don't know' or 'I was wrong'</p> Signup and view all the answers

<p>Through pretrial preparation</p> Signup and view all the answers

<p>Don't be evasive; jurors are suspicious of evasive answers</p> Signup and view all the answers

<p>By admitting to the mistake</p> Signup and view all the answers