Chapter 8 Blood And Blood Spatter Practice Exam

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.

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.

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.

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.

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.

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.

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.

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.

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.

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."

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.

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.

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.

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.

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).

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.

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.

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).