261 Questions
What is forensic science?
Forensic science is the application of science in a legal environment.
What is the aim of a forensic scientist?
The aim of a forensic scientist is to objectively examine the evidence in a scientific manner and present the results clearly.
What is the role of a forensic serologist?
The role of a forensic serologist is to analyze biological evidence.
What are some types of samples routinely analyzed by a forensic serologist?
Some types of samples routinely analyzed by a forensic serologist include blood, semen, saliva, and other bodily fluids.
What measures are needed to prevent contamination of evidence?
Measures needed to prevent contamination of evidence include using proper protective equipment, following strict protocols, and maintaining a clean and controlled laboratory environment.
Which scientist first observed the agglutination of human blood cells with human sera and determined that blood could be distinguished by a specific group or type?
Karl Landsteiner
Who developed the first confirmatory test for hemoglobin?
Ludwig Teichman
Which scientist identified differences between human blood types that formed the basis for ABO blood types?
Karl Landsteiner
Who identified Rhesus blood factors?
Karl Landsteiner
Who invented the polymerase chain reaction (PCR) techniques?
Kary Banks Mullis
According to the Locard Exchange Principle, when two objects come into contact, there is a bi-directional transfer of material between the two objects.
Every contact leaves a trace
Which of the following is NOT a discipline within the field of Forensic Science mentioned in the text?
Forensic Pathology
What is the main focus of Forensic Serology?
Investigation and analysis of biological evidence
What is the term used for the evidence left behind when two objects have come into contact?
Trace Evidence
What is the term used to describe the transfer of material between two objects when they come into contact?
Bi-directional transfer
Which of the following factors can slow down the decomposition process of a body submerged in water?
Colder temperatures
What is the waxy covering that can preserve a body called?
Adipocere
How long does it take for all soft tissues to disappear and only bones to remain?
Within one to 3 years
What can the pressure of internal gases in a decomposing body force out of the body?
Stomach contents
What can microorganisms present in soil do to buried bodies?
Decompose them
What is the term used to describe the process of body fats being hydrolyzed?
Adipocere formation
What can preserve bodies besides mummification and adipocere formation?
None of the above
What can the pressure of internal gases in a decomposing body cause to appear on the skin?
Blisters
What is the term used to describe the process of buried bodies being decomposed by microorganisms in soil?
Decomposition
What is the primary reason for slower decomposition processes when a body is submerged in water?
Colder temperatures
What are the effects of submersion in water on the decomposition process?
The decomposition process is generally slowed due to colder temperatures.
What is the term used to describe the formation of adipocere?
Adipocere is a waxy covering that can preserve a body.
How long does it take for all soft tissues to disappear and only bones to remain?
Within one to 3 years, all soft tissues will have disappeared leaving only bones.
What is the term used to describe the process of buried bodies being decomposed by microorganisms in soil?
The term used is decomposition.
What can the pressure of internal gases in a decomposing body cause to appear on the skin?
The pressure can cause fluid-filled blisters to appear on the skin.
What is the recommended solution for decontaminating equipment used in the collection and processing of biohazardous tissues or fluids?
Household bleach diluted 1:10
What is considered to be regulated medical waste (RMW) that requires specialized handling, labeling, storage, and disposal?
All of the above
What type of personal protective equipment (PPE) should be worn when handling biological, chemical, and radioactive materials?
Eye protection
What type of footwear should be used at crime scenes when there is a risk of foot injuries due to falling objects or objects piercing the sole?
Shoes that completely cover and protect the foot
When is respiratory protection necessary at certain crime scenes?
When there is potential for contamination or transfer from airborne biohazards
Which of the following is NOT a route of exposure to biological and chemical hazards mentioned in the text?
Injection
What is the primary focus of the Occupational Safety and Health Administration (OSHA) standard on blood borne pathogens?
Infection control
What are universal precautions in the context of blood borne pathogen safety?
Precautions taken to avoid direct contact with potentially infectious materials
Which of the following is NOT a protective measure recommended to avoid direct contact with potentially infectious materials?
Using regular hand washing
What is the most common hazard faced by forensic serologists?
Exposure to biological hazards
Which of the following is NOT a reason why crime scene photographs are important in a court of law?
They can be easily understood by investigators
Why is the proper documentation, collection, and preservation of blood evidence important?
To destroy its evidentiary value
What can the shape and appearance of bloodstains and smears on clothing or other surfaces provide information about?
The type of weapon used
What type of physical evidence can be found in a vehicle used for a murder or to transport a victim?
All of the above
What are the procedures for searching a vehicle used for a murder or to transport a victim?
They are the same as those at any other crime scene
What are some challenges faced in DNA testing?
Samples are susceptible to damage, degradation, and contamination. Improper handling, collection, packaging, and storage can compromise the integrity of a sample.
What are the objectives of this module?
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.
What is the importance of proper handling, collection, and storage of biological evidence?
Proper handling, collection, and storage of biological evidence is important to ensure optimum results and preserve the integrity of the sample.
What types of samples are routinely analyzed by forensic serologists?
Forensic serologists routinely analyze biological samples such as blood, cells, and tissues.
What can compromise the integrity of a DNA sample?
Improper handling, collection, packaging, and storage can easily compromise the integrity of a DNA sample.
Which of the following is NOT a characteristic of a good crime scene investigator?
Knowledge of forensic analysis
What is the most informative type of evidence in cases where the suspect and victim come into close contact or struggle with each other?
Blood
What is the most fragile evidence collected first when processing a crime scene?
DNA samples
Which reagent is used to enhance latent fingerprints and other impressions in blood on non-porous surfaces?
Amido Black
What color does amido black produce when it reacts with blood proteins?
Blue
On which type of surfaces can amido black be difficult to discern the results?
Multi-colored surfaces
What can amido black be used to enhance besides latent fingerprints?
Bloody footwear impressions
Which of the following is NOT a factor to consider when choosing a high intensity light for a forensic application?
Size of the light source
What is the purpose of using alternative light sources (ALS) in forensic investigations?
To enhance the visualization of bloodstains and other body fluids
What is the purpose of using Luminol in crime scene investigations?
To identify areas of suspected blood staining
Which of the following is NOT a recommended method for packaging loose trace evidence during transport to the laboratory?
Placing it in a plastic bag
What is the recommended packaging method for transporting a large stained item to the laboratory?
Packing it in a paper bag or envelope
What is the maximum recommended storage time for wet biological evidence in sealed plastic containers?
Less than two hours
What is the recommended packaging method for wet evidence during transportation to the laboratory?
Packing it in a paper bag or envelope
What type of containers should biological fluid reference samples be packaged in?
Leak-proof containers
What should be included in the chain of custody documentation for a sample?
The collecting person's initials
What samples are typically obtained from a victim in sexual assault cases?
Vaginal, oral, and rectal swabs
Why is it important to obtain swabs from a victim as soon as possible after the incident?
To prevent critical evidence from being destroyed or lost
What can be a good source of evidence in sexual assault cases?
Victim's underwear
How can seminal stains on highly patterned fabric be located or highlighted?
By using side lighting or special light sources
What is the purpose of collecting and recording evidence in a crime scene investigation?
To preserve the integrity of the evidence for future examination
Why is it important to collect representative samples of bloodstains from areas away from the 'action' in a crime scene investigation?
To determine the source of bloodstains leading away from the scene
What is the recommended packaging material for most items of evidence in a crime scene investigation?
Paper containers
What type of samples are commonly analyzed by forensic serologists?
Blood, hair, and saliva samples
Why should evidence never be packaged in plastic containers?
Plastic containers can contaminate the evidence
Which of the following is NOT a recommended method for storing bloodstained evidence?
Exposure to excessive heat
What is the recommended storage temperature for liquid reference samples?
4°C
Which of the following information is NOT required to be recorded for chain of custody purposes?
Final disposition of the evidence
What is the purpose of chain of custody?
To record evidence recovery, handling, and analysis
Where can further information on the collection and preservation of biological samples be found?
Which of the following is NOT a recommended method for storing biological swabs for short term storage?
Freezing the swabs
What is the minimum volume of urine needed to generate a DNA profile?
10ml
Which of the following is NOT a recommended method for collecting concentrated urine samples?
Collecting a swab from a wet biological material
What is the recommended method for collecting fingernail clippings for DNA analysis?
Using a sterile, moistened cotton swab to swab the clippings
What is the recommended method for transporting bone, teeth, skin, and tissue samples for DNA analysis?
Freezing the samples and transporting them on ice
What are the commonly used techniques to find blood in forensic casework?
Some commonly used techniques to find blood in forensic casework include luminol testing, phenolphthalein testing, and alternate light sources.
What is the significance of false positive and false negative tests in forensic biology?
False positive and false negative tests can have serious consequences in forensic biology as they can lead to incorrect conclusions and potentially wrongful convictions.
What is the difference between preliminary and confirmatory tests for blood?
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.
What is the chemistry behind preliminary tests and screening tests for blood?
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.
What is the role of specificity and sensitivity in forensic biology tests?
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.
What are the steps involved in examining evidence in separate areas/rooms to avoid cross-contamination?
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.
What are some characteristics of the item that should be noted during examination?
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.
What are the steps involved in testing suspect stains on clothing?
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).
Which type of blood vessel has strong elastic walls and helps propel blood from the heart to the major organs of the body?
Arteries
What determines whether blood oozes or spurts from an injury site?
The type of blood vessel
Which type of blood vessel returns the blood to the heart and is under much less pressure?
Veins
What is the characteristic result of damaging a high-pressure artery or arteriole?
Arterial spurt
Which type of blood vessel is much less elastic and under much less pressure?
Veins
Which tool can be used to aid in locating blood stains on black or dark clothing?
Infrared lighting
What is the first step in processing an item for the presence or absence of blood?
Perform a visual exam
What is the appearance of old and degraded blood stains?
Yellowish-greenish
What is the purpose of presumptive tests for blood?
To locate and differentiate between blood and other similarly colored stains
Which of the following is NOT a commonly used presumptive blood test?
Luminol
What is the usual test sequence for presumptive blood tests?
Add a drop of reagent to stain extract, add a drop of hydrogen peroxide, observe color change
Which reagent is commonly used in the Kastle-Meyer blood test?
Phenolpthalein
What is the benefit of using Hemastix test strips for blood detection?
They are a one-step process
What is a drawback of using Hemastix as a presumptive indicator of blood?
Difficult stain transfer
What is included in commercially available blood test kits for field testing?
All of the above
Which of the following is a confirmatory test for the presence of blood?
Microchemical test
What is the advantage of using the Takayama test as a confirmatory test for blood?
It can be used on a range of stain types
Why are microchemical tests for blood less sensitive than color tests?
They are disrupted by dirt and particulate matter
What is the main challenge in using microscopy to verify the presence of blood cells in dried bloodstains?
The need to find intact cells within the stain
What can affect the integrity of dried red blood cells in a stain?
All of the above
Which technique is considered to be a reliable method for distinguishing between different types of hemoglobin derivatives?
Spectroscopy
What is the ABAcard Hematrace test used to detect?
Human hemoglobin in a sample
Why do some laboratories choose not to use the Hematrace test as a confirmatory test for human blood?
It reacts positively with ferret blood
What is the basis for the ABAcard Hematrace test?
Antibody-antigen reaction
What precaution might laboratories take when using the Hematrace test to confirm human blood?
They may include a disclaimer in the lab report
What are the available tools used in laboratories to aid in locating stains of interest?
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.
What are the commonly used techniques to locate and test semen, saliva, and other biological fluids in forensic casework?
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.
What issues are involved in multi-section cases?
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.
Which protein is secreted by the prostate gland and aids in dissolving the cervical mucus cap to aid in sperm entry?
PSA
What is the molecular weight of the protein p30?
30,000 kD
Which test is used to detect the presence of PSA in semen?
ELISA
Which test card has a semi quantitative internal control set at 4ng/ml to aid in detecting semen concentration?
Seratec PSA Semiquant
Which test is considered to be a confirmatory test for the presence of semen?
P30 test
How long does sperm survive in the vagina after ejaculation?
1 to 8 hours
How long can intact spermatozoa persist in the vagina?
Up to 26 hours
How long can sperm heads persist in the vagina?
Up to 7 days
If abundant spermatozoa can be seen in every microscope field, when was the swab likely obtained?
1 day or less after the incident
If the spermatozoa are very few or difficult to find on the slide, when could intercourse have occurred?
5 days or more before the incident
Which of the following glands produce saliva?
Sublingual, submandibular, and parotid glands
What is the function of saliva?
All of the above
Which gland's saliva contains enzymes called amylases that facilitate the digestion of carbohydrates?
Parotid gland
Which phase of hair growth is characterized by active hair growth and contains nucleated cells in the root and surrounding sheath material?
Anagen phase
What is the main difference between human hairs and animal hairs?
Human hairs have a continuous diameter shaft, while animal hairs have an inconsistent diameter shaft
What is the average number of hairs a person sheds per day?
Up to 100 hairs
Which reagent is commonly used to identify amylase in a quantitative test?
Phadebas tablets
What is the purpose of the radial diffusion test for amylase detection?
To produce a clear area on the gel after staining with iodine solution
When is amylase testing often considered in sexual assault cases?
When saliva is used as a lubricant in the assault
Which of the following is a presumptive test for urine?
Litmus paper test
What is the basis of the Edelman test for feces?
Detection of urobilinogen
What is the purpose of the Lugol's test for vaginal secretions?
To determine the presence of glycogenated cells
Which type of evidence should not be tested for touch DNA if it contains high concentrations of DNA from another body fluid?
Bloodstains on clothing
What should be done prior to screening an item of evidence for biological analysis?
Remove trace evidence
What should be done before screening an item of evidence for latent prints?
Wear latent gloves
What specialized techniques were used in the analysis of biological evidence before DNA analysis became commonplace?
Antigen antibody reactions, electrophoresis, determination of blood group based on red cell antigens, determination of ABO blood type, secreter status, biochemical markers
What is the significance of understanding these techniques for analysts working on cold or pre-adjudicated cases?
Knowledge and understanding of these techniques may be important in analyzing old or unsolved cases
What are the advantages and disadvantages of biochemical markers and their forensic significance?
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
What is the relevance of post-conviction analysis in relation to these techniques?
Post-conviction analysis may involve re-examining evidence using these specialized techniques to confirm or challenge previous findings
In what circumstances are these techniques still routinely used?
These techniques are still routinely used in less developed countries where adequate funding for DNA analysis is not available
Which technique was commonly used in forensic serology for species identification?
Ouchterlony double diffusion
What is the principle behind the Ouchterlony double diffusion test?
Immunodiffusion and subsequent precipitation
What is the most important parameter in species identification?
Specificity
Which type of testing is less prone to false positive results?
DNA testing
In which type of cases are these techniques also applicable?
All of the above
Which of the following is NOT a blood type phenotype?
OO
How many different genotypes are possible for the ABO blood group system?
6
What is the precursor to A and B antigens?
H antigen
What percentage of people are secretors?
80%
Which two antisera are needed for a routine blood type determination?
Anti A and Anti B
Which type of electrophoresis is commonly used in DNA analysis today?
Capillary electrophoresis
What is the primary factor that determines the net charge on a protein?
The amino acid composition of the protein
What is the purpose of visualizing protein bands after electrophoresis?
To determine the presence of the proteins
What can electrophoresis be used to detect in proteins?
Subtle variations in protein charge
What is the role of gel electrophoresis in forensic settings today?
To determine the size of DNA molecules
What is the purpose of using polymorphic enzymes in forensic serology?
To determine the origin of biological stains and fluids
What is the distribution of any given marker within a population?
Dependent on the distribution of other markers
What is the product of the distribution of markers within a population?
The probability of a bloodstain having a specific combination of markers
What is the significance of finding multiple factors in a bloodstain?
The smaller the frequency of occurrence in the population
What is the relationship between the distribution of markers and regional populations?
The distribution can vary significantly between regional populations
Which of the following is true about the Group Specific Component (Ge) protein?
It is a glycoprotein found in the alpha-2 globulin fraction of serum proteins
Which of the following is true about Erythrocyte Acid Phosphatase (EAP)?
Erythrocyte acid phosphatases can be found in the cytoplasm of other tissues
Which of the following is true about genetic markers in body fluids?
Many of the genetic factors found in blood can also be found in other body fluids
Which of the following is true about the degradation of protein markers in biological materials?
Protein markers in wet samples degrade through the action of microbiological processes and endogenous enzymes
Which of the following is true about the handling and storage of biological evidence?
Drying of samples and storage under refrigerated or freezing conditions significantly slow degradation processes
What is the role of Group Specific Component (Ge) Ge protein in the body?
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.
Which body fluid is of forensic importance in cases of rape and sexual assault?
Semen
What protein markers may be present in sperm as well as seminal fluid?
Some protein markers
Which body fluid contains polymorphic markers that are found almost exclusively in it?
Saliva
Which tissues have polymorphic genetic markers that could play a role in cadaver identification?
Hair, tooth pulp, and inner ear fluid
What are the basic characteristics of blood spatter patterns?
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.
What are the factors that cause blood spatter formation?
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.
What are the limitations of blood spatter interpretation?
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.
Which blood vessel carries freshly oxygenated blood to each region of the body?
Artery
What is the main function of blood in our body?
Deliver nutrients and oxygen
What type of blood vessel has walls that expand and contract to push blood under high pressure throughout the vascular system?
Artery
What is the role of capillaries in the circulation of blood?
Supply each region of the body with freshly oxygenated blood
What is the difference between the walls of arteries and capillaries?
Arteries have strong elastic walls, while capillaries have fragile walls
Which type of spatter is produced from impact mechanisms such as beating or gunshot?
High velocity spatter
At what angle of impact will a bloodstain usually be circular?
90°
What is the range of diameters for bloodstains resulting from drops dropped over a range of 6 inches to 7 feet onto a smooth hard surface?
13-21 mm
What surface will create much less (if any) spatter compared to a rough textured surface like wood or concrete?
Glass
What is the primary factor that determines the net charge on a protein?
Type of amino acids present
Which of the following is a source of impact spatter related to gunshot wounds?
Blowback or back spatter
What is the size range of impact spatter associated with beatings and stabbings?
1-3 mm
What type of spatter is produced when blood is released when an impinging force exceeds gravity?
Projected stains
What type of spatter is produced when blood meets low velocity forces or falls freely to a surface?
Splashed blood
What is the term used to describe blood that accumulates in the lungs or airways and is forcefully expelled through the mouth and nose?
Expirated blood
Which of the following is true about the venous system?
Valves prevent the backflow of blood in veins
What color is deoxygenated blood in veins?
Blue
What initiates clot formation at the site of an open wound?
Platelet activation
What is the average terminal velocity speed for a falling blood drop?
25 feet/second
What is the stability of exposed blood drops due to?
Viscosity and specific gravity
Which type of altered stain occurs when a dried bloodstain begins to flake in the center leaving a visible outer rim, or if the central area of a partially dried bloodstain is altered by wiping or some kind of contact?
Skeletonized bloodstain
Which type of bloodstain pattern suggests the movement of a body or the infliction of further injury after the initial attack?
Drag pattern
Which type of bloodstain pattern can be caused by coughing or exhalation of clotted blood from the victim?
Expirated stain
What can cause changes in bloodstaining at a crime scene?
All of the above
What is the recommended method for recording and preserving the appearance of blood staining at a crime scene?
Photography
What is blood transfer pattern and how is it produced?
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.
What are altered stains and what are some examples?
Altered stains are stains that have been modified or changed in some way. Examples include skeletonized bloodstains and clots of blood.
How are wet bloodstains susceptible to alteration?
Wet bloodstains are susceptible to smearing, smudging, and wiping by the assailant and victim.
What are the types of blood spatter that can be found on clothing?
The types of blood spatter that can be found on clothing include transfer, flow patterns, saturation stains, and drips.
What is important to note when recording bloodstains and spatter at a crime scene?
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.
What are the basic principles of extraction, quantitation, amplification, and electrophoresis in DNA analysis?
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.
What is the role of CODIS in forensic DNA analysis?
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.
What is the difference between mDNA and Y-STR testing in DNA analysis?
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.
Which molecule carries the genetic blueprint for life?
DNA
What are the two groups of nitrogenous bases in DNA?
Purines and pyrimidines
How many hydrogen bonds are formed between adenine and thymine in DNA?
Two
What is the main technique used in RFLP DNA testing?
Gel electrophoresis
What does RFLP stand for in DNA testing?
Restriction Fragment Length Polymorphism
What is the purpose of cutting DNA into fragments in RFLP testing?
To analyze DNA variations
Which DNA extraction method is best suited for samples that are dirty or involve glues or dyes?
Organic extraction
Which DNA extraction method relies on magnetic particles to yield a clean sample free of inhibitors of the PCR/STR process?
DNA IQTM extraction
Which DNA extraction method uses Chelex beads and is a very straightforward and quick extraction method?
Chelex extraction
Which DNA extraction method uses a reverse blot to visualize and has a low level of uniqueness for a DQA genotype?
VNTR analysis
Which DNA analysis technique combines PCR and electrophoresis to amplify and separate highly discriminating short repeating units in human DNA for identification purposes?
STR testing
Which DNA analysis technique is the most current test used today and is good for typing from highly degraded samples?
STR testing
Which method is most commonly used for quantitation in PCR?
Real-time PCR
What is the purpose of amplification in the DNA process?
To make many copies of the DNA
What are the three steps involved in the polymerase chain reaction (PCR) process?
Denaturation, primer annealing, elongation
What is the role of a thermal cycler in the PCR process?
To heat and cool the DNA sample
Which type of electrophoresis is commonly used to separate DNA fragments based on their size?
Capillary electrophoresis
What is the purpose of adding a fluorescent dye tag to the primers in the amplification reaction?
To detect the DNA fragments during electrophoresis
What is the role of a camera in the electrophoresis process?
To collect data on the movement of DNA fragments
Which company offers capillary electrophoresis instruments such as the ABI 310 and ABI 3130?
Applied Biosystems
What is the purpose of real-time PCR in DNA quantitation?
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.
What are the three steps of the polymerase chain reaction (PCR) process?
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.
What is the purpose of capillary electrophoresis in DNA analysis?
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.
Which of the following is true about Y-STR testing?
It is beneficial in situations where there is limited amount of male DNA present in a sample
What is the main advantage of mitochondrial DNA (mDNA) testing?
It is less prone to degradation than nuclear DNA
What is the purpose of CODIS?
To perform DNA analysis on samples from convicted offenders and forensic casework
What is the function of robotics systems in DNA analysis?
To reduce the time required for a DNA analyst to perform extractions
What is the purpose of the Combined DNA Index System (CODIS)?
To perform DNA analysis on samples from convicted offenders and forensic casework
What is the role of an expert witness in a trial?
An expert witness is summoned to provide opinion or expert evidence based on their expertise during a trial.
What knowledge and skills are important for an expert witness to competently handle direct and cross-examination?
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.
What are the objectives of this module regarding expert testimony and courtroom presentation?
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.
Which of the following is a recommended strategy for minimizing stress and stage fright during a trial?
Admit to making a mistake if you make one
What is the recommended approach when faced with a difficult question from a juror?
Say 'I don't know' or 'I was wrong' if applicable
What is the recommended approach if you make a mistake during your testimony?
Admit to making the mistake
What is the recommended approach to dressing for a trial?
Wear conservative clothing to convey professionalism
What is the recommended approach to demeanor during a trial?
Adopt a professional demeanor without appearing overly confident
What is the recommended approach when you don't know the answer to a question?
Say 'I don't know' or 'I was wrong'
What is the recommended approach if you make a mistake during your testimony?
Admit to making the mistake
What is the recommended approach to dressing for a trial?
Wear conservative clothing to convey professionalism
What is the recommended approach to demeanor during a trial?
Adopt a professional demeanor without appearing overly confident
What is the recommended approach when you don't know the answer to a question?
Say 'I don't know' or 'I was wrong'
What is one way to minimize stress and stage fright during a trial?
Through pretrial preparation
What is one recommended approach when faced with difficult questions from jurors?
Don't be evasive; jurors are suspicious of evasive answers
How can a witness enhance their reputation for honesty if they make a mistake?
By admitting to the mistake
Test your knowledge of forensic science and the various types of evidence and tests conducted in a forensic laboratory. This quiz will challenge your understanding of the different aspects of forensic science, from minor burglaries to serious cases like murder.
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