1.
Mr. Fred Dead was reported to be missing by his wife. She knew that he owed money to a Mr. Ding Dong and she was concerned. Police arrived at the home of Mr. Dong and discovered high velocity blood spatter on the wall of the living room and walking drips measuring a vertical drop distance of 30 cm. There was no body at the location. When investigators interrogated Mr. Dong she reported that Mr. Dead came to his house and started beating on the door. Mr. Dong opened the door and was attacked by Mr. Dead. Mr. Dong grabbed a baseball bat and hit Mr. Dead in the head. Mr. Dead then ran away into the woods. Use this data to confirm or dispute the eyewitness account. What would you expect to see if Mr. Dong was telling the truth?What does the high velocity spatter pattern indicate about the events?What does the vertical drip height indicate about the events?
2.
What effect does vertical drip height have on the diameter of a blood droplet?
3.
White blood cells have proteins on the surface that allow forensics investigators to identify blood types such as A+ or B-
Correct Answer
B. False
Explanation
False. White blood cells do not have proteins on their surface that allow forensics investigators to identify blood types. Blood typing is typically done using red blood cells, which contain specific proteins called antigens that determine blood type. White blood cells, on the other hand, play a role in the immune system and do not carry blood type antigens.
4.
White blood cells
Correct Answer
A. Defend the body from pathogens
Explanation
White blood cells are an essential part of the immune system and play a crucial role in defending the body from pathogens. They identify and destroy foreign invaders such as bacteria, viruses, and fungi, preventing infections and diseases. Through various mechanisms like phagocytosis and releasing antibodies, white blood cells help to keep the body healthy and free from harmful pathogens. Therefore, the correct answer is that white blood cells defend the body from pathogens.
5.
Antibodies attach to antigens on the surface of foreign molecules that have entered the body.
Correct Answer
A. True
Explanation
Antibodies are proteins produced by the immune system in response to the presence of foreign molecules, known as antigens, in the body. These antibodies specifically bind to antigens on the surface of these foreign molecules, marking them for destruction by other immune cells. Therefore, the statement that antibodies attach to antigens on the surface of foreign molecules that have entered the body is true.
6.
Blood typing is less expensive and quicker for analyzing blood evidence than DNA profiling. Since many different people share the same type, this blood evidence is considered to be
Correct Answer
A. Class evidence
Explanation
Blood typing is considered class evidence because many different people can share the same blood type. This means that blood evidence alone cannot definitively identify a specific individual. DNA profiling, on the other hand, is more accurate and can provide individual evidence by matching specific DNA profiles to a particular person. However, DNA profiling is more expensive and time-consuming compared to blood typing, making blood typing a more cost-effective and efficient method for analyzing blood evidence.
7.
A and B proteins are found on the surface of some red blood cells. If a person’s blood contains both the A and the B proteins, then he or she has
Correct Answer
A. Type AB blood
Explanation
If a person's blood contains both the A and B proteins, it means that they have both the A and B antigens on their red blood cells. This indicates that they have type AB blood. Type AB blood is considered the universal recipient because they can receive blood from any blood type, but can only donate to other AB individuals.
8.
When samples of blood from a suspect reacts with A-antibodies and Rh-antibodies and there is no reaction with the B-antibodies. The suspect blood type is A+
Correct Answer
A. True
Explanation
The given information states that the blood sample from the suspect reacts with A-antibodies and Rh-antibodies but does not react with B-antibodies. This indicates that the blood type of the suspect is A+. A+ blood type means that the individual has A antigens on their red blood cells and Rh antigens on their red blood cells. Therefore, the correct answer is true.
9.
Results from a blood type antibody test are in the table below. What is the individuals blood type if a negative symbol represents that the antibody at the top of each column did not react with the blood sample when added to the test tube.Blood TypeA Antibody B AntibodyRh Antibody ---
Correct Answer
A. O-
Explanation
Based on the information provided in the table, the individual's blood type is O-. This is because the negative symbol under the A Antibody column indicates that the A antibody did not react with the blood sample. The negative symbol under the B Antibody column indicates that the B antibody did not react with the blood sample. And the negative symbol under the Rh Antibody column indicates that the Rh antibody did not react with the blood sample. Since none of the antibodies reacted with the blood sample, the individual's blood type is O-.
10.
A drop of blood dropped from 200 cm will be _____________________ than a blood dropped from 25 cm.
Correct Answer
A. Larger and have more satellites
11.
A blood drop that strikes a surface at 10-degrees will be __________________ than a blood drop that strikes a surface at 80-degrees.
Correct Answer
A. Longer and thinner
Explanation
When a blood drop strikes a surface at a lower angle (10 degrees), it will have more time to spread out before it comes to a stop. This results in a longer and thinner shape as the drop spreads out in a more elongated manner. On the other hand, when a blood drop strikes a surface at a higher angle (80 degrees), it has less time to spread out before stopping, leading to a shorter and wider shape as the drop spreads out in a more flattened manner.
12.
A blood droplet has a width of 5mm and a length of 10mm. What angle did the blood droplet strike the surface. Use the formula to guide you to your answer. Angle of impact = sin-1 (w/l)
Correct Answer
A. 30 degrees
Explanation
The formula given to calculate the angle of impact is Angle of impact = sin-1 (w/l), where w represents the width of the blood droplet and l represents the length of the blood droplet. In this case, the width is given as 5mm and the length is given as 10mm. Plugging these values into the formula, we get Angle of impact = sin-1 (5/10) = sin-1 (0.5). Taking the inverse sine of 0.5 gives us the angle in degrees, which is approximately 30 degrees.
13.
Agglutination is the clumping of blood cells caused by an antigen-antibody reaction
Correct Answer
A. True
Explanation
Agglutination is a process where blood cells clump together due to the interaction between antigens and antibodies. This reaction occurs when antibodies bind to antigens on the surface of blood cells, causing them to stick together. This phenomenon is commonly observed in blood typing and cross-matching tests, where the presence of clumping indicates a positive reaction. Therefore, the statement "Agglutination is the clumping of blood cells caused by an antigen-antibody reaction" is true.
14.
A two-dimensional view of the intersection of lines formed by drawing a line through the main axis of at least two drops of blood that indicates the general area of the source of the blood splatter.
Correct Answer
C. Lines of convergence
Explanation
Lines of convergence refer to the intersection of lines formed by drawing a line through the main axis of at least two drops of blood. These lines indicate the general area of the source of the blood splatter. By analyzing the angles and patterns of these converging lines, investigators can determine the point of origin of the blood spatter, providing valuable information in crime scene analysis and reconstruction.
15.
A three-dimensional view formed using lines of convergence and angles of impact of at least two different drops of blood to identify the source and location of blood splatter.
Correct Answer
B. Point of origin
Explanation
The correct answer is "point of origin." In bloodstain pattern analysis, the point of origin refers to the location in three-dimensional space where the blood droplets originated from. By analyzing the lines of convergence and angles of impact of multiple blood droplets, investigators can determine the point of origin and identify the source and location of blood splatter. This information is crucial in crime scene investigations as it can provide insights into the events that took place and help in reconstructing the sequence of events.
16.
Cells that police the body by destroying foreign materials in the blood.
Correct Answer
A. White blood cells
Explanation
White blood cells, also known as leukocytes, are responsible for protecting the body against foreign substances such as bacteria, viruses, and other pathogens. They are part of the immune system and play a crucial role in defending the body against infections. Unlike red blood cells, which are involved in oxygen transport, and platelets, which are involved in blood clotting, white blood cells are specifically designed to identify and destroy foreign materials in the blood. They do this by engulfing and digesting the invaders or by producing antibodies to neutralize them.
17.
Doughnut-shaped cells that carry oxygen throughout the body.
Correct Answer
B. Red blood cell
Explanation
Red blood cells are responsible for carrying oxygen throughout the body. They contain a protein called hemoglobin that binds to oxygen in the lungs and releases it to the body's tissues. Their doughnut shape allows them to be flexible and squeeze through narrow blood vessels. This enables them to efficiently transport oxygen to all parts of the body.
18.
Secondary drop formed when some blood breaks free from the main contact drop of blood.
Correct Answer
A. Satellite
Explanation
A satellite drop is formed when some blood breaks free from the main contact drop of blood. This means that there is a main drop of blood, and then there is another smaller drop that has separated from it. The term "satellite" is used to describe this secondary drop because it is orbiting or attached to the main drop, similar to how a satellite orbits a larger celestial body. This term helps to differentiate it from other types of drops or patterns that may be present at a crime scene.
19.
What type of blood spatter pattern is shown in the diagram?
Correct Answer
A. Arterial spurt
Explanation
The blood spatter pattern shown in the diagram is indicative of arterial spurt. Arterial spurt occurs when an artery is severed, causing blood to forcefully and rhythmically spray out in a pulsating manner. This type of spatter pattern is characterized by its distinct arcs or lines, which can be seen in the diagram. It is often associated with injuries involving major blood vessels and can provide valuable information to forensic investigators regarding the nature and location of the injury.
20.
What terms can be applied to this blood droplet?
Correct Answer
A. Spines, satellites, 90-degree vertical drip
Explanation
The blood droplet can be described as having spines and satellites, which are small secondary droplets that form around the main droplet upon impact. Additionally, the droplet is characterized by a 90-degree vertical drip, meaning that it fell straight down without any angle.
21.
Which of the following is a test that reacts with blood and emits blue light making it possible to screen large areas for bloodstains?
Correct Answer
A. Luminol
Explanation
Luminol is a test that reacts with blood and emits blue light, allowing for the screening of large areas for bloodstains. This chemical reaction occurs due to the presence of an enzyme called peroxidase in blood, which causes the luminol to produce a blue glow when it comes into contact with the iron in hemoglobin. This property of luminol makes it an effective tool for forensic investigators to detect and locate blood evidence at crime scenes.