Download 2 - Biology

The Elixir of Life
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Introduction
Read the following and complete the Pre-lab questions.
The Circulatory System is essential to the survival of humans. It carries oxygen-rich blood through a series of
blood vessels to different parts of the body. Blood is a type of connective tissue containing both dissolved
substances and specialized cells such as red blood cells and white blood cells. Red blood cells are also
commonly called erythrocytes. Erythrocytes collect oxygen from the lungs and nutrients from the digestive
tract to deliver them to each of your billions of cells. At the same time, they also collect waste products from
these cells to help remove them before they do harm. The Immune System uses blood help to fight infections
by adding its white blood cells, or lymphocytes. In addition, the Endocrine System uses the blood to send
messages throughout the body via chemicals called hormones. Blood can even form clots using platelets to
repair damaged blood vessels. Blood transfusions are necessary when a patient has lost a large amount of
blood due to injury or a medical condition. Although blood transfusions are common today, in the past they
were risky, often causing fatal immune responses in the patient. It wasn't until the turn of the century that the
reasons for these fatal reactions were discovered.
During an immune response, the body produces antibodies, which are small amino acid chains produced by
the immune system. They recognize specific foreign substances called antigens. Antigens can be anything
from a bacteria, virus, mold spore, or even a human cell – but only if it’s not your own! Antibodies are
"specific" molecules, containing recognition sites that will only attach to certain antigens. Much like a key will
only fit a specific lock, an antibody will only bind to a specific antigen. The antigen-antibody complex that
forms when an antibody binds to the surface of a complementary antigen is vital to the immune response.
Once the complex is formed, it will clump together in a large mass with other complexes. This clumping
action draws attention to the foreign substance (antigen) and attracts white blood cells called phagocytes.
Phagocytes are named for their ability to engulf and digest the clumped pathogens, called phagocytosis. Recall
that phagocytosis is a type of endocytosis where the cell membrane surrounds solid material in a type of active
transport in order to take in a large amount of material at once. In this manner, the body is able to fight off
foreign invaders.
Around 1900, Karl Landsteiner discovered that there are at least four different kinds of human blood, determined by the presence or absence of specific molecules on the surface of red blood cells. These molecules
have been designated as A and B. As person whose red blood cells carry the A molecules is said to have Type
A blood. Since this person does not have B molecules on their red blood cells, their immune system makes
antibodies against the B molecules called anti-B antibodies. Since these molecules can trigger an immune
system response if given to another person, they are referred to as antigen A or antigen B. Therefore, a person
with type A blood has A antigens and anti-B
antibodies; a person with type B blood has B
antigens and anti-A antibodies; a person with type
0 blood has neither A nor B antigens but has both
anti-A and anti-B antibodies; and a person with
type AB blood has both A and B antigens but
neither anti-A nor anti-B antibodies (see table
below). This system of blood typing is known as
the ABO system.
ABO System
Blood
Type
A
B
AB
O
Antigens on
Red Blood Cells
A
B
A and B
none
Antibodies
Anti-B
Anti-A
None
Both Anti-A and Anti-B
Can Give Can Receive
Blood To Blood From
A, AB
O, A
B, AB
O, B
AB
O, A, B, AB
O, A, B, AB
O
ABO Blood Typing and Blood Donations
It is vital to know the blood type of a patient receiving a blood transfusion. If incompatible blood types are
mixed, the immune system will attack the foreign red blood cells. For instance, if a person with type B blood is
transfused with blood type A, the recipient's anti-A antibodies will attack the incoming type A red blood cells.
The red blood cells will clump together and the red blood cells will be destroyed. This may not be a serious
problem if only a small amount of blood is transfused. If large amounts of blood are transfused, however, the
consequences can be life threatening as the large clumps of cells can block arteries and break down into toxic
substances. Type O blood, which has no antigens on red blood cells, can be given to people with any blood
type and is called the "Universal Donor". Type AB blood, which has neither anti-A nor anti-B antibodies, can
safely receive any blood type and is called the "Universal Recipient".
To ensure the safety of a person receiving a transfusion, first, both the donor's and the recipient's blood types
are identified with the ABO system. The patient's blood is exposed to two different solutions, one containing
high levels of anti-A antibodies and the other containing high levels of anti-B antibodies. Several drops of
each solution are added to separate samples of the patient's blood. The following results help determine the
individual’s blood type:
 If clumping occurs only in the suspension to which the anti-A solution was added, the blood type is A.
 If clumping occurs only in the anti-B mixture, the blood type is B.
 If there is clumping in both samples then the blood type is AB.
 The absence of clumping in any sample indicates that the blood type is O.
 DO NOW: Pre-lab Questions
Scenario
A severely injured man has been brought into a hospital emergency room. He has lost a great deal of blood. To
survive, he must receive a blood transfusion as soon as possible. Because the patient is unconscious and no
medical information can be found in his belongings, the hospital staff does not know his blood type. The
patient’s blood type must quickly be determined, and a suitable match for a transfusion must be found from
four possible donors' blood samples.
Materials Needed per Lab Group
 5 - blood typing trays
 10 - toothpicks
 simulated anti-A serum (blue)
 simulated anti-B serum (yellow)
 Set of blood samples – (5)
Procedure
1. Label each blood typing slide with a number:
 Slide #1: Mr. Smith
 Slide #2: Mr. Jones
 Slide #3: Mr. Green
 Slide #4: Ms. Brown
 Slide #5: Patient (recipient)
2. Place 3 drops of Mr. Smith's blood in each of the A and B wells of Slide #1. (leave the Rh well empty)
3. Repeat this process for the other three potential donors as well as the recipient (slide #s 2-5)
4. Add 3 drops of the simulated anti-A serum to each “A well” on the five slides.
5. Add 3 drops of the simulated anti-B serum in each “B well” on the five slides.
6. Stir each mixture for about 30 seconds with a different clean toothpick.
7. Examine each well for agglutination (clumping/cloudy).
8. Record results in Table 1. Indicate your data as “clumping” or “none”.
9. Based on your data of “clumping” or “none”, record the blood type of each potential donor and the patient.
Name:
Date:
The Elixir of Life
Pre-Lab Questions (3pts each)
1. What types of molecules does the Endocrine System use to send messages?
2. What is the main goal/purpose of the Immune System?
3. Describe the difference between an antibody and antigen.
4. What are erythrocytes?
5. What type of active transport do white blood cells use to destroy foreign materials?
6. Which blood type is the “Universal Donor”?
7. Which blood type is the “Universal Recipient”?
8. Read the procedure below. Sketch the expected results of the Blood Typing for each blood type
below.
 Shading should represent clumping.
Type A
Type B
Type AB
Type O
A
A
A
A
B
B
B
B
Table 1: Agglutination Reactions (20pts)
Anti-A Serum
Slide #1: Mr. Smith
Slide #2: Mr. Jones
Slide #3: Mr. Green
Slide #4: Ms. Brown
Slide #5: Patient
Anti-B Serum
Blood Type
Analysis Questions:
(#1-3 are 5pts each; #4-7 are 6pts each.)
1. What antigens are present on the patient's red blood cells?
What blood type is this?
2. What antibodies are present in the blood of the patient?
3. Name the potential donors that can safely donate blood to the patient.
4. Explain why is it so vital to perform blood typing prior to blood transfusions. Include a description of what
might happen if this is not done.
5. If the patient’s condition does not allow enough time to perform these tests, what other option does
Emergency Staff have for a blood transfusion? Why?
6. Suppose that Mr. Green and Ms. Brown have children. Show a Punnett Square below for their expected
offspring along with phenotypic and genotypic frequencies.
7. In the event that one of Mr. Green and Ms. Brown’s children needs a blood transfusion, which children
could receive donations from their parents? Which cannot? Explain your answers.
8. The pedigree below is a way of representing a family tree along with which members have a certain
trait. In the key below, you can see that a dark circle or square represents a person with hemophilia,
which is a recessive x-linked disorder.


Indicate the genotypes of all family members you can determine (5 pts)
XH = normal & Xh = hemophiliac
A
9. Using the pedigree above how is it possible for the couple located at position A to have boys that do not
have hemophilia? Be sure to show all of your work. (6 pts)
10. If a homozygous, normal female marries a man with hemophilia, what are the chances that their
children will have the disease (sons vs. daughters)? Be sure to show all of your work. (6 pts)