Whodunit?? Blood Typing

Subject Area	Biology – Anatomy and Biochemistry
Age or Grade	Introductory Biology – Grades 9 +
Estimated Length	45 minutes
Prerequisite knowledge/skills	Students should understand the basics of the cardiovascular system, such as gross anatomy and how blood cells deliver oxygen to the body. Students should also know the basics of blood typing, introduced in an earlier lesson plan.
Description of New Content	This activity expands on the biochemistry of ABO blood type, explaining concepts like antigen, antibody, immune response, blood type inheritance. Students will also practice using pipetmen and making scientific observations.
Goals	To give students a hands on understanding of blood type and immune reactions due to incompatibility, as well as how blood typing is used in forensic science to solve crimes.
Materials Needed	Wards “whodunit” blood typing kit 200 ul pipets 20-200 ul pipetmen ( 1 for each pair of students) 10 2ml centrifuge tubes
Procedure	Teacher setup - The teacher will tell the students that a crime has been committed and we can use blood found at the crime scene to rule out some of the suspects. The crime/suspect scenario is up to the teacher. - The Wards kit includes vials of “blood” for 4 suspects, each being type A, B, AB, or O, as well as crime scene “blood.” To expand the activity, certain vials can be split into two or three or even four containers such as 2ml centrifuge tubes. For instance, aliqot the “blood” so there are 9 suspects, 3 with blood type A, 2 with type B, 4 with type AB, and 1 with type O. Make a tube labeled “crime scene” which also contains type O blood – this will allow students to conclusively determine who is the perpetratior. Student instructions - Put on gloves and goggles - Label each blood typing slide with sample name (e.g. Suspect 1) - Place 20 uL of blood from Suspect 1 into each of the 2 wells - Add 20 uL of anti-A serum in the A well - Add 20 uL of anti-B serum in the B well - Stir each mixture with a toothpick- change toothpicks between wells to avoid cross-contamination - Record results on worksheet- agglutination indicates a positive result - Repeat steps #2-#6 for each suspect Closure: - Go over the results with the entire class. Ask the students to come up with reasons for any discrepancies in the results. Have students generate ideas for other tests that could be used to more accurately determine the culprit.
Evaluation	Students will be graded on laboratory participation, and the quality of their laboratory skills (note taking, using pipetmen, making observations)
Extensions	This activity can be used in conjunction with another forensics lab, such as fingerprint analysis, or hair sample analysis, to make stronger conclusions about which suspect is the perpetrator of the crime.
References	“Modern Biology” Textbook, Wikipedia