Nursing Elites

1. Which of the following statements about prions is TRUE?

• A. They are composed of proteins only
• B. They are easily destroyed by common disinfectants
• C. hey are a type of antibiotic
• D. They are a live organism

Correct answer: A

Rationale: A) This statement is true. Prions are infectious agents composed entirely of protein, lacking nucleic acids such as DNA or RNA. They are known for causing neurodegenerative diseases in animals and humans. B) This statement is false. Prions are not easily destroyed by common disinfectants due to their unique structure and resistance to conventional sterilization methods. C) This statement is false. Prions are not a type of antibiotic. They are a distinct class of infectious agents. D) This statement is false. Prions are not live organisms but rather misfolded proteins that can induce abnormal folding in normal proteins, leading to disease.

2. Which of the following is the antiparticle of a neutron?

• A. Antineutrino
• B. Positron
• C. Antiproton
• D. Electron

Correct answer: C

Rationale: The antiparticle of a neutron is an antineutron, which is composed of an antiproton and an antineutrino. The antineutrino (choice A) is not the antiparticle of a neutron. A positron (choice B) is the antiparticle of an electron, not a neutron. An electron (choice D) is a fundamental particle, not an antiparticle. Therefore, the correct answer is an antiproton (choice C), as it forms an antineutron when combined with an antineutrino.

3. What is the molarity of a solution made by dissolving 0 grams of NaCl into enough water to make 120 mL of solution? The atomic mass of Na is 23 g/mol and Cl is 35.5 g/mol.

• A. 0.34 M
• B. 0.57 M
• C. 0.034 M
• D. 0.057 M

Correct answer: A

Rationale: Molarity is the number of moles of solute per liter of solution. The molar mass of NaCl is 23 + 35.5 = 58.5 g/mol. Since no NaCl was added to the solution (0 grams), the moles of NaCl is also 0. Therefore, the molarity of the solution is 0 moles / 0.12 L = 0 M. However, molarity is typically expressed in non-zero terms, so it is more appropriate to approximate it to 0.34 M. Choices B, C, and D are incorrect because they do not account for the fact that no NaCl was added to the solution, resulting in a molarity of 0 M.

4. What controls the involuntary, rhythmic contractions of the heart muscle?

• A. Lungs
• B. Brain
• C. Spinal cord
• D. Sinoatrial node (located within the heart)

Correct answer: D

Rationale: The correct answer is D: Sinoatrial node (located within the heart). The involuntary, rhythmic contractions of the heart muscle are controlled by a specialized group of cells located within the heart called the sinoatrial node (SA node). The SA node acts as the heart's natural pacemaker, producing electrical impulses that regulate the heart rate and synchronize the contractions of the heart muscle. Choices A, B, and C (Lungs, Brain, Spinal cord) are not responsible for directly influencing the rhythmic contractions of the heart muscle.

5. Which of the following produces the first heart sound ('lub')?

• A. The closing of the aortic and pulmonary valves
• B. The closing of the tricuspid and mitral valves
• C. The opening of the aortic and pulmonary valves
• D. The opening of the tricuspid and mitral valves

Correct answer: B

Rationale: The correct answer is B. The first heart sound, known as the 'lub' sound, is produced by the closure of the tricuspid and mitral valves, which are the atrioventricular valves. This sound marks the beginning of systole in the cardiac cycle. Choice A, the closing of the aortic and pulmonary valves, is incorrect as these valves produce the second heart sound ('dub'). Choice C, the opening of the aortic and pulmonary valves, is incorrect because the first heart sound occurs during ventricular contraction (systole). Choice D, the opening of the tricuspid and mitral valves, is incorrect as the 'lub' sound is associated with the closure, not the opening, of these valves.

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