NAFI CFEI Forensics-Chapter 16 Exam Questions With Correct Answers

What are the two major components of blood - Answer is Cells and plasma What parts of blood are important forensically for typing? - Answer is Red blood cells and white blood cells mainly Name two preliminary and two confirmatory tests for blood? - Answer is Preliminary: phenolphthalein, fluorescein, luminol. Confirmatory: Teichmann and Takayama What is the most common test for identifying saliva? - Answer is alpha-amylase enzyme What is the only test that is absolutely confirmatory for semen? - Answer is Presence of spermatozoa Describe briefly how a blood sample is determined to be human? - Answer is The Ouchterlony and precipitin tests work the same way. An animal, such as a rabbit is injected with human serum. The animal produces antibodies to human serum in its blood. Some of the animal serum is withdrawn and used to test human blood. If a blood sample is human, the animal serum will cause the blood to agglutinate, forming a precipitin ring. What are the two major mechanisms that give rise to blood spatter patterns? - Answer is impact and projection Give an example of a type of spatter bloodstain. - Answer is examples include: impact spatter due to blunt force, impact spatter due to gunshot, expirated blood, arterials, cast off. Give an example of a type of altered bloodstain. - Answer is examples include: insect activity in blood, foreign materials in blood, void, wipe Give an example of a type of passive bloodstain. - Answer is examples include: vertical drips, swipes, flow, prints, large volume bloodstains What is a "cast off" blood spatter? - Answer is Cast off is a linear shaped blood pattern due to a bloodied object moving and ejecting blood drips though the air as it moves. Objects could be hands or objects such as knives or clubs. What is the difference between a "wipe" bloodstain pattern and a "swipe" pattern? - Answer is Wipes show movement through and existing bloodstain. Swipes deposit blood with the motion; no blood was at the position originally. What are the parts labeled A and B in the following blood drop? - Answer is A—Spine; B—Satellite Spatter Describe how the parts in question #13 can be produced - Answer is blood hits the surface moving at an angle (forward as well as downward) and the surface tension in the drop is breached causing the blood to continue its forward motion.