Nursing Elites

1. Which type of reaction is represented by the equation A + B → AB?

• A. Synthesis
• B. Decomposition
• C. Single Replacement
• D. Double Replacement

Correct answer: A

Rationale: The correct answer is 'Synthesis.' In a synthesis reaction, two or more reactants combine to form a single product. The equation A + B → AB represents a synthesis reaction where substances A and B combine to form compound AB. Choice B, 'Decomposition,' involves a single compound breaking down into two or more simpler substances, which is not the case in this equation. Choices C and D, 'Single Replacement' and 'Double Replacement,' involve the replacement of elements in compounds or the exchange of ions between compounds, neither of which is depicted in the given equation. Thus, 'Synthesis' is the most suitable classification for the reaction A + B → AB.

2. The body's first line of defense against pathogens is the innate immune system. Which of the following is NOT a component of the innate immune system?

• A. Physical barriers like skin and mucous membranes
• B. Phagocytes that engulf and destroy pathogens
• C. Inflammatory response to isolate and contain infection
• D. Production of antibodies specific to a particular pathogen

Correct answer: D

Rationale: The production of antibodies specific to a particular pathogen is a function of the adaptive immune system, not the innate immune system. The innate immune system provides immediate, non-specific defense mechanisms against pathogens, including physical barriers, phagocytes, and inflammatory responses. Choices A, B, and C are all correct components of the innate immune system. Physical barriers like skin and mucous membranes act as the first line of defense, preventing pathogens from entering the body. Phagocytes are specialized cells that engulf and destroy pathogens, while the inflammatory response helps isolate and contain infections to prevent their spread.

3. What is the 'lock-and-key' model?

• A. Protein folding
• B. Enzyme-substrate interaction
• C. Muscle contraction
• D. Blood clotting

Correct answer: B

Rationale: The 'lock-and-key' model describes the specificity of the interaction between enzymes and their substrates. In this model, the enzyme's active site acts like a lock that can only be opened by the specific substrate molecule, which serves as the key. This specific binding ensures that enzymes catalyze particular reactions and do not interact with other molecules indiscriminately. Protein folding (option A) is the process by which a protein attains its functional three-dimensional structure but is not directly related to the lock-and-key model. Muscle contraction (option C) and blood clotting (option D) are complex biological processes but are not directly associated with the lock-and-key model of enzyme-substrate interaction.

4. What happens to the acceleration of an object when the force acting on it is increased, assuming the mass remains constant?

• A. Acceleration increases
• B. Acceleration decreases
• C. Acceleration remains constant
• D. Acceleration becomes zero

Correct answer: A

Rationale: According to Newton's second law of motion, acceleration is directly proportional to the force acting on an object when the mass is constant. Therefore, if the force acting on an object is increased while the mass remains constant, the acceleration of the object will also increase. This relationship is described by the formula F = ma, where F is the force applied, m is the mass of the object, and a is the acceleration. When force increases, acceleration increases, and vice versa, as long as the mass stays the same. Choice B (Acceleration decreases) is incorrect because acceleration and force have a direct relationship. Choice C (Acceleration remains constant) is incorrect because acceleration changes in response to changes in force. Choice D (Acceleration becomes zero) is incorrect because increasing force does not make acceleration zero; it actually increases it.

5. What is the stoichiometric coefficient of nitrogen (N2) in the balanced equation for the Haber process: N2 + 3H2 → 2NH3?

• A. 1
• B. 2
• C. 3
• D. 4

Correct answer: A

Rationale: In the balanced equation for the Haber process: N2 + 3H2 → 2NH3, the stoichiometric coefficient of nitrogen (N2) is 1. This means that one molecule of nitrogen reacts with three molecules of hydrogen to produce two molecules of ammonia. The coefficient '1' indicates the mole ratio of N2 in the reaction. Choice B, 2, is incorrect because it represents the coefficient for ammonia (NH3) in the balanced equation. Choice C, 3, is incorrect as it corresponds to the coefficient of hydrogen (H2). Choice D, 4, is not the correct stoichiometric coefficient for nitrogen (N2) in this equation.

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