Download Forensic Serology Homework (Blood Chapter

Blood Homework (Forensic Serology)
Part 1 Biology Review:
1. Complete the Punnett squares and answer the questions that follow.
Subject: Dale
Father’s genotype
A
A
B
Subject: Maria
Father’s genotype
B
B
A
A
B
Mother’s
genotype
O
Mother’s
genotype
Mother’s
genotype
Subject: Greg
Father’s genotype
A
O
a. Among this group of people, which blood type(s) is most likely to be expressed? Which blood
type is least likely to be expressed? Explain your answers.
b. What blood type is Greg most likely to have? Explain your answer.
c. Which person is least likely to have type B blood? Explain your answer.
d. In which, if any, of these people may a recessive gene express itself? Explain your answer.
Maria’s genotype
2. Suppose that Greg and Maria have a child. Construct all of the possible Punnett squares for that
child and answer the following questions.
Greg’s genotype
a. What blood type(s) is the child most likely to have?
b. What genotype(s) is the child most likely to have?
c. If Maria and Greg have the same genotype, what blood type is the child most likely to
have? What are the chances that the child will have type O blood? Explain your answers.
O
Part 2: Blood Biology
3. What three questions should an investigator answer when examining an apparent dried blood
stain?
4. What blood factors are the most important for properly matching a donor and recipient for a
transfusion?
5. What technique mostly replaced blood typing when matching bloodstain evidence with a
particular individual?
6. What is plasma? What percentage of blood content does plasma occupy?
7. Which of the following types of cells are not contained in plasma? phagocytes, leukocytes,
erythrocytes, platelets
8. What are antigens and antibodies? What part of the blood contains antibodies?
9. Describe how antibodies and antigens determine one’s ABO blood type.
10. What is the fourth important antigen other than A, B, and O?
11. What are the four major blood types found in humans? What is your blood type? How did you
find out?
12. What happens when serum containing B antibodies is added to red blood cells carrying the B
antigen? Will the same thing happen if serum containing B antibodies is added to red blood cells
carrying the A antigen? Explain your answer.
13. How much blood is there in the average adult human?
14. What happens if a person with type AB blood is given a transfusion of type A blood? Explain.
What happens in the opposite transfusion?
15. What is the probability of an AB and Rh- blood type combination? Show your work.
16. Define a presumptive test.
17. What property of blood is used in most presumptive tests?
18. Name the most common color test for blood and briefly describe how it identifies bloodstains.
19. Briefly describe how luminol is used to detect bloodstains.
20. What is a secretor?
21. Define serology. How is it used in forensic investigations? What is its most widespread
application, and in what other areas related to forensic science is it finding application?
22. What test can determine whether blood is human or animal? What is the basis for this test? Why is
the serum used in this test called human antiserum?
Part 3: Bloodstain pattern analysis
23. How do the hardness and porosity of a surface affect blood spattering on that surface?
24. How does a blood spatter analyst determine the direction of travel of blood striking an object?
25. A drop of blood striking a surface at right angles produces a stain of what shape? As the angle
decreases, what happens to the shape of the stain?
26. When examining a blood spatter in a two-dimensional configuration, how does an analyst
determine the area from which the blood emanated?
27. What is a “cast-off” blood spatter?
28. What is the difference between a “wipe” bloodstain pattern and a “swipe” pattern?