Expert answer:Blood Forensic Lab
Expert answer:Attached the documentsYou need to read and answer correctly thinking in Forensic Crime Solutions
forensic_lab.docx
hs_for_03_12_lab_instructions_blood_a11y.docx
3.13_blood.docx
Unformatted Attachment Preview
Forensic LAB
Unit 3 – Lab 3.14 – Blood
The “Blood” lab is our next lab in the Trace Evidence Units. Overall, you are working as a
forensic scientist to analyze blood evidence from an interrupted burglary at a woman’s
home at the beach. A suspect has been apprehended, and you will be analyzing evidence
from the house and the suspect (shirt and gym bag). In addition to the suspect and the
victim, the victim’s dog was also involved and there may be blood from the dog as part of
the evidence. You will determine if the samples are blood (using a luminol test), if the
samples are human blood (using a precipitin test), and the blood type if the blood is human
(make sure you remember how determine blood type from lesson 3.13).
In order to conduct this lab, you will need to print out the student guide and lab
instructions. As you read through the background information (in 3.14), make sure to take
notes on blood samples. You may also need to refer back to your notes from lesson 3.13.
All of the information for the lab is in the 3.14 lesson, so work through the background and
evidence carefully, recording your findings on the lab instructions. As long as you follow
what is in the course and the information on the instructions, you will find the lab is very
straightforward to complete.
Quiz 3.14 has 8 questions and consists of questions from your lab results. Pay careful
attention when answering questions that can have more than one answer (questions 7 and 8)
– make sure to choose all correct answers. You may use your completed lab instructions
when taking the quiz.
What’s the Story?: Mugging at a Beach House
– This activity describes a fictional crime story about a mugging at a beach house
Analyzing Blood Evidence
Police collect blood evidence.
Police investigated the scene of the robbery, assault, and battery. Investigators photographed the
house. Police collected blood evidence from the house, the articles recovered with the suspect, and
the suspect’s clothing.
Police did presumptive tests of the blood evidence at the crime scene. They sent samples to you, the
forensic scientist. Police also sent sketches of the crime scene and recovered items. You must
analyze the samples to help resolve the crime.
Is it blood?
You will need to analyze the results of luminol tests. Remember that luminol interacts with
hemoglobin to produce a blue glow that can be seen in dark or semidark conditions, especially
under UV light.
Is it human blood?
Once a sample has been identified as blood, you will need to determine whether it is human blood.
Ms. Kinsey’s dog was cut in the struggle, so some of the samples may have come from the dog.
Sorting through the human and animal blood is essential to reconstructing the crime.
Precipitation Test
Positioned in the center of the space is a surface labeled, agar matrix. Positioned on the surface are
two oval shapes. The ovals represent substances. The substance on the right is dark. This substance
is labeled, antigen parentheses unknown blood. The substance on the left is light. This substance is
labeled, antibody parentheses from rabbit. A sentence at the top of the space: The sample of
possible human blood is placed in one well of a gel test plate. The antibody is placed in the opposite
well.
When the presentation activates, the two substances in the gel plate spread toward each other. At
that time, this sentence appears at the top of the space: Both antibodies and antigens diffuse
through the gel.
As the substances continue to diffuse, they overlap. When that happens, a long, thin, very dark
stripe, or line, appears in the center of the place where they overlap. The sentence at the top of the
space: If the human antigen is present, it binds to the antibody and precipitates in a line. If there is
no antigen present, then no line will form.
Whose blood is it?
According to Lisa Kinsey, a man attacked her in the hallway of her beach house. Is Richard
Sullivan the man? The blood samples sent to you may have key information. For each blood
sample, you will identify the blood type in order to link the blood sample to an individual.
Remember that blood type is determined by adding anti-A and anti-B sera. Each blood type in turn
can be either Rh+ (has Rh antigen) or Rh– (no Rh antigen).
Blood Type Test
Type A
Type B
Type AB
Type O
Anti-A
serum
Anti-B
serum
Print the Laboratory Instructions: Blood.
Follow the directions in the Laboratory Instructions. You will have two days to complete
the lab.
Go to the next screen to access the sketches, luminol, precipitin, and blood type test
results that you will need for this lab.
The sketches and tests are organized according to the location of the blood samples as
follows:
•
•
•
Hallway
Living Room
Shirt and Gym Bag
Hallway
Luminol Test: Hallway
Precipitin Test: Hallway
Blood Type Test: Hallway
Living Room
Luminol Test: Living Room
Precipitin Test Results: Living Room
Blood Type Test Results: Living Room
Shirt and Gym Bag
Luminol Test: Shirt and Gym Bag
Precipitin Test: Shirt and Gym Bag
Blood Type Test: Shirt and Gym Bag
Science | Laboratory Instructions | Laboratory: Blood
Laboratory Instructions
Laboratory: Blood
Materials
Supplied
•
•
•
•
•
•
Student Guide
Laboratory Guidelines
Crime Scene Sketches (online)
Luminol Tests (online)
Precipitin Tests (online)
Blood Type Tests (online)
Also Needed
•
scientific calculator (optional)
Safety
•
Review the Laboratory Guidelines before conducting the lab.
Crime Summary
This is a fictional case. On Sunday, July 17, 2011, at 8:20 p.m., Atlantic Beach police and paramedics responded
to a 911 emergency call at the beachfront home of 28-year-old Lisa Kinsey. Ms. Kinsey suffered cuts on her
hands and a minor injury to the back of her head. Her dog was treated for an apparent knife cut to his paw. Ms.
Kinsey explained that she and her dog were returning from a walk on the beach. When they came to the
beachside door, she noticed it was ajar and the doorframe was damaged. When she entered, there was a tall,
dark-haired man in the hallway outside one of the bedrooms. The man wore jeans and a shirt, but she did not get
a good look at his face. Her dog immediately attacked the man. The man dropped a gym bag and pulled a knife.
After a short struggle with the dog, he cut the dog with the knife, and the dog ran off. He then proceeded to attack
Ms. Kinsey. She defended herself, but the man threw her into a wall. She hit the back of her head and fell
forward. As she lay on the ground, she saw the man pick up the gym bag, and run out the door toward the beach.
After he left, she slowly got up and called 911.
Police investigated the scene of the robbery and assault. Drawers had been dumped. Ms. Kinsey said money and
jewelry were missing. There were traces of blood on the carpet in the hallway and the living room. Officers
sprayed the areas with luminol to find other traces of blood and took samples.
At 10:00 p.m., the investigators were informed that a man was arrested for DUI. His name was Richard Sullivan.
He lived in nearby Morehead City and worked construction in Atlantic Beach. He had wounds to his left arm. The
wounds could have been caused by dog bites and knife cuts. His shirt was stained with blood. When asked about
the blood and wounds, he claimed he had injured himself while working construction on a nearby beach house
that day. Police also found a bloodstained gym bag containing cash. The man’s clothes and the gym bag were
taken as possible evidence. As required by law, a blood sample was taken to confirm the results of the
Breathalyzer test administered at the site of arrest. The Breathalyzer test registered 0.10%, above the state’s
legal limit of 0.08%. Police have provided sketches from the crime scene and the results of their luminol tests.
Your lab has run precipitin tests and blood type tests on each sample.
You will find the crime scene sketches, luminol results, precipitin test results, and blood types for each sample
online. The sketches and tests are organized according to the location of the blood samples as follows:
•
•
•
Hallway
Living Room
Shirt and Gym Bag
© 2015 K12 Inc. All rights reserved.
Copying or distributing without K12’s written consent is prohibited.
Page 1 of 4
Science | Laboratory Instructions | Laboratory: Blood
Part 1: Blood Evidence: Hallway
You will analyze the bloodstains from the hallway first.
1. Locate the sketch of the Hallway online. You will notice blood spots numbered 1 through 9 on the floor and
wall.
2. Click the Luminol button at the bottom of the screen to see the results of the luminol test. Which of the
numbered blood spots are blood? Check the positive results in the “Blood?” column of the Blood Analysis
Table below. Note that you will use this table for other parts of the lab.
3. Next click the Precipitin button. A precipitin test was run on each blood sample. Which of the numbered blood
spots are human blood? Check the positive results in the “Human Blood?” column.
4. Finally, click the Blood Type button. The blood-typing tests were run in multi-well plates. Anti-A antibodies,
anti-B antibodies, or anti-Rh antibodies were added to the samples shown. Where appropriate, write the blood
type in the Blood Type column. (An “X” indicates that the test was not run.)
Blood Analysis Table
Sample
Number
Blood?
Human
Blood?
Blood
Type
Sample
Number
1
15
2
16
3
17
4
18
5
19
6
20
7
21
8
22
9
23
10
24
11
25
12
Richard
Sullivan
13
Lisa
Kinsey
Blood?
Human
Blood?
Blood
Type
14
Part 2: Blood Evidence: Living Room
Once you have finished testing the bloodstains in the hallway, go to the next screen to locate the sketch of the
living room. You will see blood spots numbered 10–17 on the sketch. Repeat Steps 1–4 from Part 1, recording the
results in the Blood Analysis Table.
© 2015 K12 Inc. All rights reserved.
Copying or distributing without K12’s written consent is prohibited.
Page 2 of 4
Science | Laboratory Instructions | Laboratory: Blood
Part 3: Blood Evidence: Shirt and Gym Bag
Once you have finished testing the bloodstains in the living room, go to the next screen to locate the sketch of
Richard Sullivan’s shirt and the gym bag. You will see blood spots numbered 18–25 on the sketch. Repeat Steps
1–4 from Part 1, recording the results in the Blood Analysis Table.
Part 4: Analyze the Results
Blood samples from Richard Sullivan and Lisa Kinsey were sent to your lab. The results of a blood type test are
shown below. Write their blood types in the Blood Analysis Table.
Use the results in the Blood Analysis Table to answer the following questions.
Hallway:
1. Return to the sketch of the hallway. What is the most likely source of samples 1, 2, 3, and 5? Why did the
lab decide not to run a blood type test on these samples?
•
Answer here.
2. Who is a possible source of sample 6? What part of the story would be corroborated by samples 1, 2, 3, 5,
and 6?
•
Answer here.
3. Who is a likely source of samples 7, 8, and 9?
•
Answer here.
4. Who is a possible source of sample 4? What part of the story would be corroborated by samples 4, 7, 8, and
9?
•
Answer here.
Living Room:
1. Who is a likely source of samples 11 and 12?
•
Answer here.
2. Who is a possible source of samples 10, 13, and 14? What part of the story would be corroborated by
samples 10–14?
•
Answer here.
3. What might be the source of samples 15, 16, and 17?
•
Answer here.
Shirt and Gym Bag:
1. Whose blood is on the shirt? Explain how you think the blood got on the shirt.
© 2015 K12 Inc. All rights reserved.
Copying or distributing without K12’s written consent is prohibited.
Page 3 of 4
Science | Laboratory Instructions | Laboratory: Blood
•
Answer here.
2. Whose blood is on the gym bag? Explain how you think the blood got on the gym bag.
•
Answer here.
Evaluate Lisa Kinsey’s account of the events.
•
Answer here.
Do you think Richard Sullivan should be a person of interest in this crime?
•
Answer here.
© 2015 K12 Inc. All rights reserved.
Copying or distributing without K12’s written consent is prohibited.
Page 4 of 4
3.13 BLOOD
Blood and bloodstain evidence are often recovered at crime scenes. The evidence is first analyzed
by chemical tests to determine if it is actually blood. After the substance is confirmed as blood,
forensic scientists perform a variety of tests to determine if it is human blood, the blood type, and
the relationship of the blood to suspects and/or victims.
In this lesson, you will learn about blood and the various tests that forensic scientists use to analyze
blood evidence.
What’s the Story?: The Mad Carpenter
The mad carpenter had blood on his clothes.
In Germany in 1900, two boys went missing. Their dismembered corpses were found scattered in
the woods. Suspicion fell on a traveling carpenter named Ludwig Tessnow.
A local farmer identified Tessnow as the man who had killed and hacked sheep in his field.
Investigators saw stains on Tessnow’s boots and clothing, which he claimed were from wood dye.
Three years earlier, Tessnow had been questioned in a similar crime and had given the same story.
About that time, Paul Uhlenhuth developed a test to distinguish blood from dye and animal blood
from human blood. Investigators used the test on Tessnow’s clothing. The test showed dye, sheep
blood, and human blood on the clothing. Tessnow was tried, convicted, and executed in 1904.
Composition of Blood
What is blood?
Blood is a mixture of cells and fluid. The cells make up 45% of blood volume:
•
•
•
Red blood cells (erythrocytes) – They carry oxygen bound to the protein hemoglobin.
White blood cells(leukocytes) – They protect you from disease and foreign cells; they also
produce antibodies.
Platelets (thrombocytes) – They clot blood to prevent, slow, and stop bleeding.
Blood plasma is fluid that makes up 55% of the blood volume and consists of dissolved salts,
water, fats, and proteins. Blood serum is blood plasma minus some of its proteins and all of its
clotting factors. Both blood serum and blood plasma contain antibodies.
Plasma is the liquid component of blood. Serum is the liquid component of clotted blood. Serum
lacks the clotting factors, but it has antibodies.
Order from left to right lines (1) plasma (2) white blood cel (3) platelet (4) red blood cell
(5)blood vessels
Chemical tests depend on hemoglobin.
Most chemical tests for blood interact with hemoglobin . Hemoglobin is a protein in the blood that
consists of polypeptide chains with iron groups (hemes) in the center of each chain. Hemoglobin
carries oxygen bound to the heme groups within it.
Some chemical tests are based on oxidation reactions that occur in the presence of hemoglobin.
These tests show a color change. Other tests are based on chemicals that form crystals with
hemoglobin.
•
•
Red blood cells contain several hundred thousand hemoglobin molecules.
Oxygen binds to heme on the hemoglobin molecule
Immunological tests depend upon antigen-antibody reactions.
The second type of blood tests involve the immune system. Antigens are foreign substances—
proteins, bacteria, viruses, or toxins. When exposed to an antigen, some white blood cells produce
specific antibodies to the antigen. This is called an immune response.
Antigens are usually proteins on cell surfaces or freely floating. The antibodies bind to the antigens
and clump together. Your body then removes the clumps.
The antibody-antigen reaction is specific. For example, antibodies against flu virus bind only to that
flu virus’s antigens, not to cold virus antigens. Scientists take advantage of this specificity in
designing blood tests.
•
White blood cells recognize and respond to foreign molecules, called antigens, to protect
the body.
Forensic Blood Tests
Blood is collected as evidence at a crime scene.
Bloodstains at a crime scene may still be wet when investigators arrive. Wet blood evidence, such
as soaked fabrics or paper, should be dried first and then placed in sealed, paper evidence bags. If
moisture is not allowed to dry before the bag is sealed, it could support the growth of bacteria or
molds.
Dried bloodstains are removed by cutting the paper or fabric where possible. Each piece of blood
evidence is collected and stored separately.
Is it really blood?
How do investigators know that a stain is blood? The first step is to do a presumptive test. The
presumptive test determines whether the stain is possibly blood.
One common presumptive test is the Kastle-Meyer test . In this test, an investigator treats the
bloodstain with hydrogen peroxide (H2O2) and phenolphthalein (a color indicator). The hydrogen
peroxide and phenolphthalein react in the presence of hemoglobin, changing the color of clear
phenolphthalein to pink.
The Kastle-Meyer test is very sensitive to blood, but other substances can also cause the reaction
and color change. Potatoes and horseradish are two substances that give a positive Kastle-Meyer
test. If a stain has a positive Kastle-Meyer test, it is likely blood. But further testing is necessary.
Luminol detects hidden blood.
Luminol is another chemical used for presumptive tests. Investigators spray luminol and H2O2 on
an area where blood is suspected. If hemoglobin is present, a reaction takes place that emits a blue
glow, which is seen in dark or semidark conditions, or under ultraviolet light. Luminol detects
traces of blood that may not be visible otherwise. Play the video to see hidden blood.
Similar to the Kastle-Meyer test, other substances, such as copper and horseradish, give a positive
result for luminol tests.
Detecting Hidden Blood
The close-up image shows a seemingly clean tile floor. A gloved hand appears in the frame, holding
a narrow light that emits a violet glow. As the light passes over the floor, it illuminates a number of
previously unseen drops on the tile floor. When the light is removed, the floor again appears to be
clean.
Confirmative tests verify blood.
If the presumptive test is positive, a sample will be sent to the lab for a confirmative test to verify
that the evidence is blood.
Commonly used tests are the Takayama and Teichmann tests. These tests involve adding chemicals
to the sample. The chemicals combine with hemoglobin to form microcrystals. The shape of the
crystals determines whether blood is present in the sample.
Is the blood human?
Once a stain is confirmed to be blood, investigators must determine whether it is human blood.
The precipitin test is a standard test for this purpose.
This test is an immunological test, because it is based on an antigen-antibody reaction. In this case,
the antibody comes from an animal, usually a rabbit that has been injected with human blood (the
antigen). The rabbit forms antibodies in response to human blood, and these antibodies are then
used to detect human blood in the precipitin test.
Precipitation Test
Positioned in the center of the space is a surface labeled, agar matrix. Positioned on the surface are
two oval shapes. The ovals represent substances. The substance on the right is dark. This substance
is labeled, antigen parentheses unknown blood. The substance on the left is light. This substance is
labeled, antibody parentheses from rabbit. A sentence at the top of the space: The sample of
possible human blood is placed in one well of a gel test plate. The antibody is placed in the opposite
well.
When the presentation activates, the two substances in the gel plate spread toward each other. At
that time, this sentence appears at the top of the space: Both antibodies and antigens diffuse
through the gel.
As the substances continue to diffuse, they overlap. When that happens, a long, thin, very dark
stripe, or line, appears in the center of the place where they overlap. The sentence at the top of the
space: If the human antigen is …
Purchase answer to see full
attachment
How it works
- Paste your instructions in the instructions box. You can also attach an instructions file
- Select the writer category, deadline, education level and review the instructions
- Make a payment for the order to be assignment to a writer
- Download the paper after the writer uploads it
Will the writer plagiarize my essay?
You will get a plagiarism-free paper and you can get an originality report upon request.
Is this service safe?
All the personal information is confidential and we have 100% safe payment methods. We also guarantee good grades