The nurse is reviewing the immune system prior to discussing the actions with a patient. What type of cell should the nurse identify that is involved in cell-mediated immunity and has a cytotoxic action on tumor cells?

Correct Answer: C

Rationale: The correct answer is C: Natural killer cells. Natural killer cells are involved in cell-mediated immunity and have cytotoxic actions on tumor cells. They are part of the innate immune system and can directly kill infected or cancerous cells. Lysosomes (A) are organelles within cells that break down waste materials. Memory cells (B) are a type of immune cell that "remembers" previous infections to mount a faster response upon re-exposure. Histocompatibility cells (D) are involved in recognizing self from non-self in transplant situations, not in cytotoxic actions on tumor cells.

Correct Answer: C

Rationale: The correct answer is C: proteins. Gas vesicles are gas-filled structures found in certain bacteria and archaea to provide buoyancy. The membrane of gas vesicles is predominantly composed of proteins that form a semi-permeable barrier to trap gas. Proteins are essential for the structure and function of gas vesicles. Triglycerides (A) are not typically found in membrane structures, phospholipids (B) are more common in cell membranes, and lipopolysaccharides (D) are typically found in the outer membrane of Gram-negative bacteria, not in gas vesicle membranes.

Correct Answer: A

Rationale: Plaques are clear areas caused by virus infection in a lawn of cultured cells. This is because viruses infect cells, causing cell death and lysis, which results in clear areas. Choice B is incorrect because stained areas are not typically associated with plaques. Choices C and D are also incorrect as they refer to virus and bacterial colonies, respectively, not plaques.

Correct Answer: D

Rationale: The correct answer is D: H₂. In anaerobic respiration, H₂ can act as a terminal electron acceptor, so it is not an incorrect example. Nitrate, hydrogen sulfate, and iron hydroxide are all examples of terminal electron acceptors in anaerobic respiration. H₂ is commonly used in microbial processes as an electron donor, not as a terminal electron acceptor. This is because H₂ is typically oxidized to produce energy, rather than accepting electrons.

Correct Answer: B

Rationale: Step-by-step rationale: 1. Bronchitis is characterized by inflammation of the bronchi, leading to coughing and mucus production. 2. Asthma involves inflammation and narrowing of the airways but is not specific to bronchi. 3. Emphysema is a lung disease involving damage to the air sacs, not specifically inflammation of bronchi. 4. Tuberculosis is a bacterial infection affecting the lungs, not primarily characterized by bronchial inflammation. Summary: Bronchitis is the correct answer as it specifically involves inflammation of the bronchi, while asthma, emphysema, and tuberculosis do not primarily exhibit this characteristic.