Nursing Elites

1. How do vaccines work?

• A. By directly killing pathogens
• B. By introducing weakened or inactive versions of pathogens to trigger an immune response
• C. By stimulating the immediate production of specific antibodies
• D. None of the above

Correct answer: B

Rationale: Vaccines work by introducing weakened or inactive versions of pathogens to trigger an immune response in the body. This exposure helps the immune system recognize and remember the pathogen, enabling a faster and more effective response upon future exposure. Vaccines do not directly kill pathogens but prepare the immune system for a potential encounter, enhancing protection. They also do not stimulate the immediate production of specific antibodies as the immune response takes time to develop upon vaccination. Choice A is incorrect because vaccines do not kill pathogens directly; they prime the immune system to recognize and respond to them. Choice C is incorrect because while vaccines lead to the production of specific antibodies, it is not immediate, as it takes time for the immune response to develop and produce these antibodies.

2. What is the fatty sheath that insulates some nerve fibers and speeds up signal transmission called?

• A. Myelin sheath
• B. Dura mater
• C. Pia mater
• D. Arachnoid mater

Correct answer: A

Rationale: The correct answer is A: Myelin sheath. The myelin sheath is a fatty layer that surrounds and insulates some nerve fibers, facilitating the rapid transmission of signals along the nerve fibers. Choices B, C, and D (Dura mater, Pia mater, and Arachnoid mater) are layers of the meninges, protective membranes that surround the brain and spinal cord. The primary function of the meninges is to protect and support the central nervous system, not to insulate nerve fibers for signal transmission.

3. Which of the following contains a single immature egg cell that is released during ovulation?

• A. oocytes
• B. follicles
• C. ovaries
• D. fallopian tubes

Correct answer: B

Rationale: Follicles are the structures in the ovaries that contain the oocytes (immature egg cells). During ovulation, a single mature egg cell is released from a mature follicle in the ovary. The other options (A. oocytes, C. ovaries, D. fallopian tubes) do not specifically refer to the structure that contains the immature egg cell that is released during ovulation.

4. What is the product of the reaction between hydrochloric acid (HCl) and sodium hydroxide (NaOH)?

• A. NaCl + H2O
• B. NaOH + HCl
• C. Na2Cl + H2O
• D. NaClO3 + H2

Correct answer: A

Rationale: When hydrochloric acid (HCl) reacts with sodium hydroxide (NaOH), it forms sodium chloride (NaCl) and water (H2O) according to the following chemical equation: HCl + NaOH -> NaCl + H2O. Therefore, the correct answer is NaCl + H2O (Choice A). This reaction is a classic acid-base neutralization reaction where the acid (HCl) reacts with the base (NaOH) to form a salt (NaCl) and water (H2O). Choice B (NaOH + HCl) is incorrect because the order of the reactants matters in a chemical reaction, and in this case, HCl is the acid reacting with NaOH. Choices C (Na2Cl + H2O) and D (NaClO3 + H2) are incorrect because they do not represent the products of the reaction between HCl and NaOH as per the balanced chemical equation.

5. Which of the following best describes the process of osmosis?

• A. Movement of molecules against their concentration gradient
• B. Movement of water across a selectively permeable membrane
• C. Movement of water and solutes together
• D. Movement of large molecules through a membrane

Correct answer: B

Rationale: The correct answer is B. Osmosis is the process where water moves across a selectively permeable membrane from an area of low solute concentration to an area of high solute concentration. Choice A is incorrect because osmosis does not involve movement against the concentration gradient. Choice C is incorrect because osmosis primarily involves the movement of water, not water and solutes together. Choice D is incorrect as osmosis specifically refers to the movement of water molecules, not large molecules, through a membrane.

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