Nokea
In order to grow, all microorganisms require:
- A. liquid water
- B. organic substances
- C. oxygen
- D. warm temperatures
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.
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Which of the following is not a consequence of anaphylactic shock?
- A. Constriction of airways
- B. Loss of blood pressure
- C. Hives
- D. Binding of allergen-specific IgE to mast cells
Correct Answer: D
Rationale: The correct answer is D because the binding of allergen-specific IgE to mast cells is actually a key event in anaphylactic shock, leading to the release of inflammatory mediators. Constriction of airways (A), loss of blood pressure (B), and hives (C) are all consequences of anaphylactic shock due to the systemic release of histamine and other mediators. IgE binding to mast cells triggers the release of these mediators, causing the symptoms associated with anaphylaxis. Therefore, D is the correct answer as it is not a consequence but rather an initiating event in anaphylactic shock.
A nurse is teaching the client with systemic lupus erythematosus about prednisone. What information is the priority?
- A. Might make the client feel jittery or nervous.
- B. Can cause sodium and fluid retention.
- C. Long-term effects include fat redistribution.
- D. Never stop prednisone abruptly.
Correct Answer: D
Rationale: The correct answer is D because abruptly stopping prednisone can lead to adrenal insufficiency due to suppression of the body's natural cortisol production. Adrenal insufficiency can be life-threatening. Priority is given to this information to ensure the client's safety. Choice A is incorrect as jitteriness or nervousness are common side effects but not the priority. Choice B is incorrect as sodium and fluid retention are potential side effects but not as critical as avoiding adrenal insufficiency. Choice C is incorrect as fat redistribution is a long-term effect but not as immediate as the risk of adrenal insufficiency.
When a B cell undergoes class switching it allows the cell to:
- A. Differentiate into a memory cell
- B. Make two or more antibody classes at the same time
- C. Stop making one class of antibody and begin to make another
- D. Receive costimulatory signals from any T helper cell subset
Correct Answer: C
Rationale: Rationale:
1. Class switching in B cells involves changing the class of antibody produced.
2. This allows the B cell to stop making one class of antibody and start making another.
3. This process enhances the immune response by generating antibodies with different functions.
4. Differentiating into a memory cell (choice A) is a separate process from class switching.
5. Making two or more antibody classes simultaneously (choice B) is not a characteristic of class switching.
6. Costimulatory signals from T helper cells (choice D) are important for B cell activation but not directly related to class switching.
Epithelial cells at mucosal sites have barrier functions exerted through several mechanisms. These mechanisms do not include:
- A. Secretion of mucins
- B. Secretion of antimicrobial peptides
- C. Phagocytosis of microbes
- D. Tight junctions
Correct Answer: C
Rationale: The correct answer is C: Phagocytosis of microbes. Epithelial cells primarily act as a physical barrier to prevent the entry of microbes. Phagocytosis is a function of immune cells, not epithelial cells. A: Secretion of mucins helps trap pathogens. B: Secretion of antimicrobial peptides aids in defense. D: Tight junctions form a physical barrier between cells. Therefore, phagocytosis is not a direct mechanism exerted by epithelial cells at mucosal sites.
Which of the following is a characteristic of the constant region of a T cell receptor?
- A. Mediates antigen binding
- B. Anchors the receptor in the T cell membrane
- C. Interacts with MHC molecules
- D. Structurally diverse amongst all T cell receptors
Correct Answer: B
Rationale: The correct answer is B: Anchors the receptor in the T cell membrane. The constant region of a T cell receptor is responsible for anchoring the receptor in the T cell membrane, providing stability and structural support. This region does not mediate antigen binding (choice A), as that function is carried out by the variable region. It also does not directly interact with MHC molecules (choice C), which is primarily the role of the variable region. Lastly, the constant region is not structurally diverse amongst T cell receptors (choice D), as it remains relatively consistent within a specific T cell subtype.