Which of the following statements describes an active cellular membrane exchange process?

Correct Answer: A

Rationale: The correct answer is A. In active transport, energy is expended to move substances against their concentration gradient. Sodium moving out of cells and potassium moving into cells is an example of active transport because it requires energy to pump these ions across the cell membrane against their concentration gradients. Choices B, C, and D describe passive processes where substances move along their concentration gradients without the input of energy.

Correct Answer: A

Rationale: The correct answer is A: live and can cause infection. Patients who are immunocompromised, like those receiving long-term steroids after an organ transplant, should not receive live vaccines because the live attenuated organisms in these vaccines can cause infections in individuals with weakened immune systems. Choice B is incorrect because attenuated vaccines are live but weakened, not mutated. Choice C is incorrect because while inactive, attenuated vaccines are not infectious. Choice D is incorrect because attenuated vaccines are not pathogenic; they are attenuated (weakened) forms of the pathogen.

Correct Answer: B

Rationale: Neutrophils are the first responders to a bacterial infection. They are phagocytes that engulf and destroy bacteria, playing a crucial role in the early stages of the immune response. Eosinophils are primarily involved in combating parasitic infections and allergic reactions, not bacterial infections. Leukotrienes are signaling molecules that contribute to inflammation and immune responses, but they are not cells. Monocytes are another type of white blood cell that differentiates into macrophages and dendritic cells, playing a role in immune response but not as immediate as neutrophils.

Correct Answer: C

Rationale: The correct answer is C: Complement, clotting, and kinin systems. These are the three main plasma protein inflammatory mediator systems. The complement system helps in inflammation and immune responses, the clotting system is involved in blood coagulation, and the kinin system regulates inflammation and blood pressure. Choice A is incorrect because interferon is not part of the plasma protein inflammatory mediator systems. Choice B is incorrect because the fibrinolytic system is not a primary inflammatory mediator system. Choice D is incorrect because acute phase reactants are not part of the plasma protein inflammatory mediator systems.

Correct Answer: A

Rationale: The correct answer is Vitamin B12. Vitamin B12 deficiency can lead to megaloblastic anemia, a condition characterized by the production of abnormally large and immature red blood cells. Lower extremity paresthesias, such as tingling or numbness, are common neurological symptoms associated with vitamin B12 deficiency. Folate deficiency can also cause megaloblastic anemia but is not typically linked to lower extremity paresthesias. Iron deficiency leads to microcytic anemia, not megaloblastic anemia. Vitamin K deficiency is associated with bleeding tendencies, not megaloblastic anemia or paresthesias.