1. 12 January 2015
Blood Types

2. Do Now
What do you know about blood types? What causes differences in blood types? What use do you think they might have for forensics? What questions do you have?

3. Blood Factors
Blood factors are proteins found in blood that differ between individuals
More than 250 different blood factors!
Some blood factors are also antigens – substances that are capable of causing an immune response in people who don’t have them
The blood factors that cause the greatest immune response belong to the ABO and Rh groups.

4. Antigen – Antibody Reactions
Antigens are foreign substances that provoke an immune response – usually the release of antibodies that bind to and attack them
Where are they found?
Surface of pathogens (e.g. viruses, bacteria, etc.)
Vaccines (that’s why they work!)
Allergens (e.g. pollen, dust, etc.)
Cancer cells (foreign b/c cell has mutated)
Transplanted tissue / organs
Antibodies are proteins produced by white blood cells that bind to and destroy antigens. Antibodies are specific to certain antigens

5. Agglutination
When antibodies bind to RBCs, they cause agglutination, or clumping
Why is this bad?
Initially, clumps clog small capillaries, causing pain and reduced blood flow
Later, RBCs that are bound to the antibodies lyse or break open, releasing hemoglobin into the blood – which can cause kidney failure

6. ABO blood group
In the ABO blood group, there are two antigens, “A” and “B”, found on the surface of RBCs
You can have one type of antigen, both types, or neither
You develop antibodies to the type of antigens you don’t have during infancy

7. Turn & Talk
Determine whether each statement is correct as written. If it is not correct, re-write it.
The “A” and “B” antigens are examples of blood factors.
If you have type “B” blood then you have “B” antigens.
If you have type “AB” blood then you have “O” antibodies.
For people who have allergies, pollen is an antibody.
Agglutination occurs when antibodies bind to the antigens in blood.
Antibodies are found on the surface of red blood cells.
Correct!
“A” antigens
Do not have “A” or “B” antibodies
antigen
Correct!
In the blood plasma

8. ABO blood group & transfusions
The key to transfusions:
You cannot give a person blood that has antigens for which they have antibodies, otherwise, their immune system will attack that blood.
Fill out the chart …
Blood Type
Can donate to
Can receive from A B AB O
Which type is the universal donor? Which type is the universal recipient?

9. ABO blood group & transfusions
The key to transfusions:
You cannot give a person blood that has antigens for which they have antibodies, otherwise, their immune system will attack that blood.
Fill out the chart …
Blood Type
Can donate to
Can receive from A
 A, AB
 A, O B
 B, AB
 B, O AB
 AB
 A, B, AB, O O  O
Which type is the universal donor? O Which type is the universal recipient? AB

10. Rh Blood Group
The Rh blood group describes ~45 different (but similar) antigens on RBCs. These antigens are called antigen “D”
People are Rh + if they have any of the various D antigens. They are Rh – if the do not have any D antigens.
Unlike the ABO system, Rh- people must be sensitized to the D antigen before developing antibodies. That means Rh- people will NOT have an agglutination reaction the first time they encounter Rh+ blood … but they will if they have it a second time.
Blood Type
Can donate to
Can receive from
Rh+
Rh-

11. Rh Blood Group
The Rh blood group describes ~45 different (but similar) antigens on RBCs. These antigens are called antigen “D”
People are Rh + if they have any of the various D antigens. They are Rh – if the do not have any D antigens.
Unlike the ABO system, Rh- people must be sensitized to the D antigen before developing antibodies. That means Rh- people will NOT have an agglutination reaction the first time they encounter Rh+ blood … but they will if they have it a second time.
Blood Type
Can donate to
Can receive from
Rh+
Rh-, Rh+
Rh-

12. Rh Blood Group & Pregnancy
Rh- moms can carry a Rh+ baby if the dad is Rh+
The first baby is usually born without any problems, but during delivery, some of the baby’s D antigens will contact the mom’s blood, causing her to be sensitized to D antigens.
If the mom becomes pregnant with a second Rh+ baby, her immune system will attack the baby’s blood, causing brain damage or death to the fetus.
This can be prevented by giving the
mother medicine that prevents her from
developing antibodies against D
antigens.
No problems occur if the baby is Rh- and the mom is Rh+

13. Blood Typing
Antiserum is a solution that contains antibodies against a specific antigen (i.e. antiserum A contains type A antibodies). Blood type is determined by adding antiserum A, B, and D to blood and observing whether or not agglutination occurs.

14. Blood Typing
Antiserum is a solution that contains antibodies against a specific antigen (i.e. antiserum A contains type A antibodies). Blood type is determined by adding antiserum A, B, and D to blood and observing whether or not agglutination occurs.

15. Congo-line review Front two rows… Back rows …
On the front of a notecard / scrap paper, draw a possible result for a blood typing test.
On the back, write the correct blood type.
Back rows …
On the front of a notecard / scrap paper , write a question about blood transfusions.
On the back, write the answer.

16. How is blood type used in forensics?
To identify people or link suspects to crime scenes
To identify paternity

17. Genetics Refresher
We have two versions – or alleles – of every gene. One inherited from our mom, one from our dad.
The two alleles (genotype) interact to determine our trait (phenotype) in predictable ways.
Some alleles are dominant, some are recessive. Dominant genes show their trait and ‘cover up’ recessive genes.
IA (A) and IB (B) are dominant to i (O).
D (+) is dominant to d (–)
Some alleles are codominant. This means both alleles fully express their trait.
IA and IB are codominant with each other.

18. Genotype to Phenotype IAiDD iidd IB IB Dd IA IB dd IB iDd
What blood type will result from each genotype?
IAiDD
iidd
IB IB Dd
IA IB dd
IB iDd

19. Genotype to Phenotype IAiDD A+ iidd O- IB IB Dd B+ IA IB dd AB-
What blood type will result from each genotype?
IAiDD A+
iidd O-
IB IB Dd B+
IA IB dd AB-
IB iDd B+

20. Phenotype to Genotype A+ AB- O- B+
What are the possible genotypes for each blood type? A+
AB- O- B+

21. Phenotype to Genotype A+ IAIADD, IAiDD, IAIADd, IAiDd AB- IAIBdd
What are the possible genotypes for each blood type?
A+ IAIADD, IAiDD, IAIADd, IAiDd
AB- IAIBdd
O- iidd
B+ IBIBDD, IBiDD, IBIBDd, IBiDd
Other important vocab –
Homozygous – both alleles for one gene are the same (e.g. ii)
Heterozygous – the two alleles for one gene are different (e.g. Iai)

22. Punnett Squares
Punnett Squares are a tool for predicting the traits that will result from crossing certain genotypes.

23. Monohybrid (One gene) Crosses
We do ….
Iai X ii
IBIB X Iai
You do …
3. Dd X dd
4. IAIB X ii

24. Dihybrid (Two gene) Crosses
We do …
IAiDd X iiDd
AB- X iiDD
You do …
IBiDd X IAiDD
IAidd X IBiDd

25. Closure, Exit Ticket, HW Closure – Exit Ticket – Homework–
Unit question? Something new? LP? TOK?
Exit Ticket –
Pick a blood type. For that type, list
Antibodies
Antigens
Blood typing test results
To whom can it donate?
From whom can it receive?
Genotype
Homework–
Homework sheet due next class. Major quiz in two classes.