Nursing Elites

1. What happens to the wavelength of a wave when its frequency increases while the speed remains constant?

• A. Wavelength increases
• B. Wavelength decreases
• C. Wavelength remains the same
• D. Wavelength becomes zero

Correct answer: B

Rationale: When the speed of a wave is constant and the frequency increases, the wavelength must decrease to keep the speed constant. The speed of a wave is determined by the product of frequency and wavelength (speed = frequency x wavelength). If the frequency increases while the speed remains constant, the wavelength has to decrease proportionally to maintain the speed unchanged. Therefore, as the frequency increases, the wavelength decreases to ensure that the speed of the wave remains constant. Choice A is incorrect because as frequency increases, wavelength decreases. Choice C is incorrect as the wavelength cannot remain the same when frequency increases while speed is constant. Choice D is incorrect as the wavelength cannot become zero under these conditions.

2. What is the purpose of sodium bicarbonate when released into the lumen of the small intestine?

• A. It works to chemically digest fats in the chyme.
• B. It decreases the pH of the chyme to prevent harm to the intestine.
• C. It works to chemically digest proteins in the chyme.
• D. It increases the pH of the chyme to prevent harm to the intestine.

Correct answer: D

Rationale: Sodium bicarbonate, when released into the lumen of the small intestine, functions to increase the pH of the acidic chyme coming from the stomach. This increase in pH helps neutralize the acidity of the chyme, creating a more optimal environment for the digestive enzymes in the small intestine to function properly. Maintaining a slightly basic pH in the small intestine is crucial for overall digestion and absorption of nutrients. Choices A, B, and C are incorrect. Sodium bicarbonate does not chemically digest fats or proteins in the chyme, and it does not decrease the pH of the chyme as it actually increases the pH to prevent harm to the intestine.

3. Which of the following structures in the respiratory system is responsible for gas exchange?

• A. Trachea
• B. Alveoli
• C. Bronchi
• D. Diaphragm

Correct answer: B

Rationale: The correct answer is B: Alveoli. The alveoli in the lungs are responsible for gas exchange. They have a thin membrane that allows for the exchange of oxygen and carbon dioxide between the air in the lungs and the blood in the capillaries surrounding them. This process is essential for respiration, providing oxygen to the body's tissues and removing carbon dioxide, a waste product of cellular metabolism. Choices A, C, and D are incorrect. The trachea is a passageway that carries air to and from the lungs but is not directly involved in gas exchange. Bronchi are airway passages that further divide into smaller bronchioles leading to the alveoli but do not perform gas exchange themselves. The diaphragm is a muscle involved in the breathing process by aiding in inhalation and exhalation, but it is not the structure responsible for gas exchange in the respiratory system.

4. How many moles of oxygen are required to completely react with 5 moles of propane (C3H8) in the combustion reaction?

• A. 5 moles
• B. 10 moles
• C. 15 moles
• D. 20 moles

Correct answer: C

Rationale: In the balanced chemical equation for the combustion of propane (C3H8): C3H8 + 5O2 → 3CO2 + 4H2O, 1 mole of propane (C3H8) reacts with 5 moles of oxygen (O2). To determine the moles of oxygen required to react with 5 moles of propane, we use the molar ratio: 5 moles propane x 5 moles oxygen / 1 mole propane = 25 moles oxygen. However, since the question specifically asks for the moles of oxygen needed to react with 5 moles of propane, the correct answer is 15 moles of oxygen. Choice A, 5 moles, is incorrect because this is the amount of propane provided, not the oxygen required. Choice B, 10 moles, is incorrect as it does not correspond to the molar ratio in the balanced equation. Choice D, 20 moles, is incorrect as it is not in line with the stoichiometry of the reaction.

5. What are substances that stimulate adaptive immunity called?

• A. Peptides
• B. Phagocytes
• C. Prions
• D. Platelets

Correct answer: A

Rationale: Substances that stimulate adaptive immunity are called peptides. Peptides are short chains of amino acids that play a crucial role in activating the immune response by interacting with immune cells such as T cells and B cells. Peptides are important in antigen presentation and recognition, leading to the development of specific immune responses against pathogens. Choice B, phagocytes, are cells that engulf and digest pathogens but are not substances that stimulate adaptive immunity. Choice C, prions, are infectious agents made of misfolded proteins and are not related to stimulating adaptive immunity. Choice D, platelets, are cell fragments involved in blood clotting and have no direct role in stimulating adaptive immunity.

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