The nurse is caring for a patient who is experiencing an immune response involving B and T cells. Which type of immunity is the patient demonstrating?

Correct Answer: B

Rationale: The correct answer is B: Humoral immunity. Humoral immunity involves B cells producing antibodies to target pathogens. B cells are responsible for producing antibodies that circulate in the blood and lymph to neutralize pathogens. This type of immunity is specific to antigens and is a key component of the adaptive immune response. Passive immunity (A) is when antibodies are transferred from one individual to another, not involving B and T cells directly. Acquired immunity (C) is a broad term encompassing both humoral and cell-mediated immunity. Cell-mediated immunity (D) involves T cells directly targeting infected cells, not B cells producing antibodies.

Correct Answer: C

Rationale: The correct answer is C: chloroplasts. Cyanobacteria do not have chloroplasts because they are prokaryotic organisms and do not possess membrane-bound organelles like chloroplasts found in eukaryotic cells. Instead, they perform photosynthesis using thylakoids, which are membrane-bound compartments where photosynthesis occurs. Gas vesicles are also present in cyanobacteria and help regulate their buoyancy. Heterocysts are specialized cells that aid in nitrogen fixation, a process that allows cyanobacteria to convert atmospheric nitrogen into a form that can be used by the organism. Therefore, the absence of chloroplasts in cyanobacteria makes choice C the correct answer.

Correct Answer: A

Rationale: The correct answer is A: liquid water. Water is essential for all cellular functions, including metabolism and nutrient transport. Without water, microorganisms cannot grow or survive. Organic substances (choice B) are important as a nutrient source, but water is indispensable for growth. While oxygen (choice C) and warm temperatures (choice D) can enhance growth for some microorganisms, they are not universally required for all microorganisms to grow.

Correct Answer: B

Rationale: The correct answer is B: carotenoids. Carotenoids are photosynthetic pigments that are found in all prokaryotic and eukaryotic photoautotrophs. They play a key role in capturing light energy for photosynthesis. Chlorophyll c, phycobilins, and phycocyanin are not found in all prokaryotic and eukaryotic photoautotrophs. Chlorophyll c is primarily found in certain algae, phycobilins are specific to cyanobacteria and red algae, and phycocyanin is a type of phycobilin found in cyanobacteria. Carotenoids are the only pigment that is universally present across all photoautotrophs.

Correct Answer: C

Rationale: The correct answer is C: Autoimmune diseases. This is because autoimmune diseases occur when the immune system mistakenly attacks the body's own tissues or organs. In this condition, the immune system fails to recognize self from non-self, leading to inflammation and tissue damage. A: Allergies involve an exaggerated immune response to harmless substances, not attacking self-tissues. B: Immunodeficiencies result in a weakened immune system, making it less effective at fighting infections, not attacking self-tissues. D: Delayed hypersensitivity is a type of immune response that occurs hours to days after exposure to an allergen, not involving the immune system attacking self-tissues. In summary, autoimmune diseases are characterized by the immune system targeting the body's own tissues or organs, distinguishing them from allergies, immunodeficiencies, and delayed hypersensitivity.