1.
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 reaction occurs due to the presence of iron in hemoglobin, the protein found in red blood cells. When luminol comes into contact with blood, it undergoes a chemical reaction known as chemiluminescence, resulting in the emission of blue light. This property of luminol makes it a valuable tool in forensic investigations for detecting and locating bloodstains, even in cases where they may not be visible to the naked eye.
2.
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 consistent with an arterial spurt. Arterial spurt patterns occur when a major artery is severed, causing blood to be forcefully ejected in a rhythmic and pulsating manner. This type of spatter is characterized by distinct and elongated droplets that travel a significant distance from the source. The presence of this pattern suggests that the victim likely experienced a severe injury to an artery, resulting in the forceful expulsion of blood.
3.
What effect does vertical drip height have on the diameter of a blood droplet?
4.
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. While white blood cells do have proteins on their surface, these proteins are not used to identify blood types such as A+ or B-. Blood typing is determined by the presence or absence of specific antigens on the surface of red blood cells, not white blood cells. White blood cells are primarily involved in the immune response and fighting off infections.
5.
White blood cells
Correct Answer
A. Defend the body from pathogens
Explanation
White blood cells are a crucial component of the immune system and are responsible for defending the body from pathogens. They identify and destroy harmful bacteria, viruses, and other foreign substances that can cause infections or diseases. Through various mechanisms such as phagocytosis and the production of antibodies, white blood cells play a vital role in protecting the body against harmful invaders. Therefore, the correct answer is that white blood cells defend the body from pathogens.
6.
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. 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 is true.
7.
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. In contrast, DNA profiling 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.
8.
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 the B proteins, it means that they have both A and B antigens on the surface of their red blood cells. This combination of antigens is characteristic of type AB blood, which is the correct answer. Type AB blood is considered the universal recipient because it can receive blood from any blood type without causing an immune response.
9.
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
When samples of blood from a suspect react with A-antibodies and Rh-antibodies but do not react with B-antibodies, it indicates that the suspect has the A+ blood type. This is because the presence of A-antibodies and Rh-antibodies suggests the presence of the A antigen and the Rh factor on the red blood cells, while the lack of reaction with B-antibodies indicates the absence of the B antigen. Therefore, the correct answer is True.
10.
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 given in the table, the individual's blood type is O-. This can be determined because the antibodies A, B, and Rh did not react with the blood sample when added to the test tube. Therefore, the individual does not have the A antigen, the B antigen, or the Rh antigen on their red blood cells, indicating that their blood type is O- (O negative).
11.
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
Explanation
The question is comparing the behavior of a drop of blood dropped from different heights. When a drop of blood is dropped from a greater height (200 cm), it will experience a longer fall and therefore have more time to accumulate other smaller blood droplets or particles, which can be considered as "satellites" in this context. This will make the drop of blood appear larger and have more satellites compared to a drop of blood dropped from a shorter height (25 cm).
12.
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 a longer and thinner shape compared to a blood drop that strikes the surface at a higher angle (80-degrees). This is because the lower angle allows the blood drop to spread out more horizontally, resulting in a longer and narrower shape. On the other hand, a higher angle causes the blood drop to spread out more vertically, resulting in a shorter and wider shape.
13.
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
14.
Agglutination is the clumping of blood cells caused by an antigen-antibody reaction
Correct Answer
A. True
Explanation
Agglutination is indeed the clumping of blood cells caused by an antigen-antibody reaction. This reaction occurs when antibodies bind to antigens on the surface of red blood cells, causing them to clump together. This process is commonly used in blood typing and cross-matching procedures, where the presence or absence of specific antigens on red blood cells can determine blood compatibility for transfusions. Therefore, the statement "Agglutination is the clumping of blood cells caused by an antigen-antibody reaction" is true.
15.
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 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. This term is used in forensic analysis to determine the point of origin or the location from where the blood splatter originated. By analyzing the angle and intersection of these lines, investigators can narrow down the possible location of the blood source.
16.
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 splatter originated from. By analyzing the lines of convergence and angles of impact of multiple blood drops, investigators can determine the point of origin, which helps in understanding the source and location of the blood splatter. This information is crucial in forensic investigations to reconstruct the events that occurred at a crime scene.
17.
Cells that polish the body by destroying foreign materials in the blood.
Correct Answer
A. White blood cells
Explanation
White blood cells are responsible for defending the body against foreign materials such as bacteria, viruses, and other pathogens. They do this by engulfing and destroying these foreign substances through a process called phagocytosis. This process helps to remove harmful materials from the bloodstream and maintain the overall health and well-being of the body. Therefore, white blood cells are the cells that polish the body by destroying foreign materials in the blood.
18.
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 have a unique doughnut-shaped structure that allows them to efficiently transport oxygen to all the tissues and organs. These cells contain a protein called hemoglobin, which binds to oxygen in the lungs and releases it in other parts of the body. The shape of red blood cells increases their surface area, enabling them to carry more oxygen. Therefore, red blood cells are the correct answer in this context.
19.
Secondary drop formed when some blood breaks free from the main contact drop of blood.
Correct Answer
A. Satellite
Explanation
The term "secondary drop" refers to a smaller droplet of blood that forms when some blood breaks free from the main contact drop of blood. The word "satellite" accurately describes this concept, as it implies a smaller object orbiting around a larger one, similar to how a secondary drop forms around the main drop of blood. Therefore, the correct answer is "satellite."
20.
What terms can be applied to this blood droplet?
Correct Answer
A. Spines, satellites, 90-degree vertical drip
Explanation
This blood droplet can be described as having spines and satellites, which are small secondary droplets that form around the main droplet upon impact. Additionally, it has a 90-degree vertical drip, indicating that it fell straight down without any horizontal movement.