how do the killer t cells recognize infected cells

ATI TEAS 7

ATI TEAS Practice Science Test

1. How do killer T cells recognize infected cells?

A. The B cells flag the infected cells with amino acids.
B. Tiny bits of the virus's RNA are left around the cell.
C. Macrophages show up to help consume the infected cell.
D. The T cells have receptors that recognize the proteins the virus leaves on the surface of the cell.

Correct answer: D

Rationale: Killer T cells recognize infected cells by detecting viral proteins displayed on the surface of these cells. The T cells possess receptors specifically designed to identify these viral proteins, allowing them to target and eliminate the infected cells. Choice A is incorrect because B cells are not directly involved in the recognition process of infected cells by killer T cells. Choice B is incorrect because tiny bits of the virus's RNA being left around the cell is not how killer T cells primarily recognize infected cells. Choice C is incorrect because while macrophages play a role in immune responses, they do not directly assist in the recognition of infected cells by killer T cells.

2. Which statement accurately describes cytokinesis in animal cells?

A. Which statement accurately describes cytokinesis in animal cells?
B. A cell plate forms in the center of the dividing cell, eventually separating the cytoplasm into two daughter cells.
C. A cell plate forms in the center of the dividing cell, eventually separating the cytoplasm into two daughter cells.
D. The nucleus elongates and pulls apart, physically dividing the cytoplasm into two.

Correct answer: B

Rationale: A) This statement is a duplicate of option C and does not accurately describe cytokinesis in animal cells. B) In animal cells, during cytokinesis, a cleavage furrow forms in the center of the dividing cell. This furrow deepens and eventually pinches the cytoplasm into two daughter cells. This process is distinct from plant cells, where a cell plate forms. C) This statement is a duplicate of option A and does not accurately describe cytokinesis in animal cells. D) This statement describes the process of nuclear division (mitosis) rather than cytokinesis, which is the division of the cytoplasm.

3. Which of the following is NOT a component of the body's innate immune response?

A. Physical barriers like skin and mucous membranes
B. Phagocytes that engulf and destroy pathogens
C. Inflammatory response to isolate and contain infection
D. Production of antibodies specific to a particular pathogen

Correct answer: D

Rationale: The production of antibodies specific to a particular pathogen is a function of the adaptive immune response, not the innate immune response. Innate immunity involves nonspecific defense mechanisms like physical barriers, phagocytes, and inflammation, which provide immediate protection against pathogens without prior exposure. Antibody production is a characteristic of adaptive immunity, where the body generates specific antibodies in response to encountering a pathogen for the first time. Therefore, option D is the correct answer as it does not align with the immediate and nonspecific nature of the innate immune response.

4. Positron emission tomography (PET) scans utilize a key property of positrons for medical imaging. What is this property?

A. High mass
B. Positive charge
C. Extreme stability
D. Identical behavior to electrons

Correct answer: B

Rationale: Positron emission tomography (PET) scans utilize the property of positrons having a positive charge. Positrons are the antimatter counterpart of electrons, having the same mass but opposite charge. When a positron collides with an electron, they annihilate each other, producing gamma rays that can be detected by the PET scanner to create images of the body's internal structures and functions. Choice A is incorrect because positrons have the same mass as electrons. Choice C is incorrect as positrons are not extremely stable due to their tendency to annihilate when they encounter electrons. Choice D is incorrect as positrons exhibit different behavior than electrons due to their opposite charges.

5. What is the recommended daily intake of protein for adults to maintain healthy muscle mass?

A. 0.5 grams per kilogram of body weight
B. 1 gram per kilogram of body weight
C. 1.5 grams per kilogram of body weight
D. 2 grams per kilogram of body weight

Correct answer: B

Rationale: The recommended daily intake of protein for adults to maintain healthy muscle mass is typically around 1 gram per kilogram of body weight. This amount can vary based on individual factors such as activity level, age, and overall health status. Consuming an adequate amount of protein is essential for muscle repair and growth, as well as overall health and functioning of the body. Choices A, C, and D are incorrect because they suggest protein intake levels that are either too low (A) or unnecessarily high (C and D) for maintaining healthy muscle mass. Excessive protein intake can strain the kidneys and may not provide additional benefits for muscle health beyond the recommended levels.