Nursing Elites

1. Which of the following is a special property of water?

• A. Water does not easily flow through phospholipid bilayers.
• B. A water molecule's oxygen atom does not allow fish to breathe.
• C. Water is highly cohesive, which explains its high melting point.
• D. Water cannot self-hydrolyze and decompose into hydrogen and oxygen.

Correct answer: C

Rationale: Water is highly cohesive, meaning it is attracted to itself due to its hydrogen bonding properties. This cohesion is the reason why water has a high melting point compared to other liquids of similar molecular weight. It is crucial for the existence of life on Earth as it allows water to remain a liquid within a wide range of temperatures, providing a stable environment for biological processes to occur. Choices A, B, and D are incorrect. Water's cohesive property does not directly relate to its ability to flow through phospholipid bilayers, assist fish in breathing, or self-hydrolyze into hydrogen and oxygen.

2. In the reaction 2H2 + O2 → 2H2O, how many moles of oxygen are required to react completely with 4 moles of hydrogen?

• A. 1
• B. 2
• C. 3
• D. 4

Correct answer: B

Rationale: The balanced chemical equation indicates that 2 moles of H2 react with 1 mole of O2 to produce 2 moles of H2O. To determine how many moles of O2 are required to react with 4 moles of H2, you can use the mole ratio from the balanced equation: 2 moles of H2 react with 1 mole of O2. Therefore, to react completely with 4 moles of H2, you would need 2 moles of O2 (4 moles H2 ÷ 2 moles H2 per 1 mole O2). Hence, 2 moles of oxygen are required to react completely with 4 moles of hydrogen. Choices A, C, and D are incorrect because they do not reflect the correct stoichiometry as defined by the balanced chemical equation.

3. What effect does doubling the net force applied to an object have on its acceleration, assuming mass remains constant?

• A. Acceleration doubles
• B. Acceleration is halved
• C. Acceleration remains the same
• D. Acceleration quadruples

Correct answer: A

Rationale: According to Newton's second law of motion, acceleration is directly proportional to the net force applied to an object when mass is constant. Therefore, if the net force is doubled, the acceleration of the object will also double. This relationship is expressed by the formula F=ma, where F is the net force, m is the mass, and a is the acceleration. When mass is constant, doubling the force applied will result in a proportional doubling of acceleration. Choices B, C, and D are incorrect because doubling the net force does not halve, maintain, or quadruple the acceleration; it directly and proportionally increases the acceleration.

4. Which of the following is responsible for the body's fight-or-flight response?

• A. Pancreas
• B. Adrenal glands
• C. Thyroid gland
• D. Pituitary gland

Correct answer: B

Rationale: The correct answer is B: Adrenal glands. The adrenal glands are responsible for the body's fight-or-flight response. During stressful situations, the adrenal glands release hormones like adrenaline and noradrenaline, initiating the fight-or-flight response. These hormones prepare the body to either confront or flee from a perceived threat.\nChoice A - Pancreas: The pancreas is primarily responsible for producing insulin and regulating blood sugar levels, not the fight-or-flight response.\nChoice C - Thyroid gland: The thyroid gland is responsible for producing hormones that regulate metabolism, not directly involved in the fight-or-flight response.\nChoice D - Pituitary gland: The pituitary gland regulates various endocrine functions by releasing hormones, but it is not the primary gland responsible for the fight-or-flight response.

5. Which of the following stimulates adaptive immunity?

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

Correct answer: C

Rationale: The correct answer is C: Prions. Prions are infectious proteins that can stimulate an adaptive immune response by triggering the production of specific antibodies. Peptides are fragments of proteins and can be processed and presented by antigen-presenting cells to activate T cells, which play a role in adaptive immunity. Phagocytes, such as macrophages, are part of the innate immune system and are involved in engulfing and destroying pathogens, but they do not directly stimulate adaptive immunity. Platelets are primarily involved in blood clotting and are not directly related to stimulating adaptive immunity.

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