Nursing Elites

1. What phenomenon occurs when a wave encounters a change in medium causing a change in its speed and direction?

• A. Refraction
• B. Reflection
• C. Diffraction
• D. Interference

Correct answer: a

Rationale: Refraction happens when a wave changes its speed and direction due to encountering a change in medium.

2. Lysosomes are known as "suicide bags" of the cell. What enzymes do they contain?

• A. Hydrolytic enzymes
• B. Ligases (bonding enzymes)
• C. Transferases (molecule transfer)
• D. Oxidoreductases (redox reactions)

Correct answer: A

Rationale: Lysosomes are membrane-bound organelles containing hydrolytic enzymes responsible for breaking down various macromolecules, cellular waste, and foreign substances. These enzymes perform hydrolysis, a process where water molecules are used to break down larger molecules into smaller components. This function earned lysosomes the nickname 'suicide bags' as they can initiate cell death (apoptosis) by releasing their enzymes when needed. Ligases, transferases, and oxidoreductases are enzymes with different functions such as forming bonds, transferring molecules, and catalyzing redox reactions, respectively, which are not typically found in lysosomes. Therefore, the correct answer is A: 'Hydrolytic enzymes.'

3. Which of the following is an example of a decomposition reaction?

• A. 2H2 + O2 → 2H2O
• B. CaCO3 → CaO + CO2
• C. 2Na + Cl2 → 2NaCl
• D. N2 + 3H2 → 2NH3

Correct answer: b

Rationale: Decomposition reactions involve the breakdown of a compound into simpler substances.

4. During vigorous exercise, the respiratory rate increases to:

• A. Meet the increased demand for oxygen in working muscles
• B. Eliminate excess carbon dioxide more slowly
• C. Conserve energy for physical activity
• D. Decrease the amount of oxygen delivered to the body

Correct answer: A

Rationale: During vigorous exercise, the respiratory rate increases to meet the increased demand for oxygen in working muscles. When we exercise vigorously, our muscles require more oxygen to produce energy through aerobic metabolism. Increasing the respiratory rate allows more oxygen to be taken in and transported to the muscles via the bloodstream to support this increased demand. Option A is correct because it accurately reflects the physiological response of the respiratory system to vigorous exercise, ensuring that working muscles receive sufficient oxygen for optimal performance.

5. Which type of energy is possessed by an object in motion?

• A. Potential energy
• B. Kinetic energy
• C. Thermal energy
• D. Chemical energy

Correct answer: b

Rationale: Kinetic energy is the energy possessed by an object in motion.

6. A scientist observes a new chemical reaction and proposes a mechanism for how it occurs. What is the BEST way to test this mechanism?

• A. Simulate the reaction using computer models.
• B. Design experiments to manipulate predicted intermediate steps.
• C. Compare the reaction to similar known reactions.
• D. Publish the mechanism in a scientific journal.

Correct answer: B

Rationale: Designing experiments to manipulate predicted intermediate steps is the best way to test the proposed mechanism because it directly tests the validity of the proposed mechanism by manipulating the specific steps involved. This approach allows for empirical validation of the proposed mechanism and provides concrete evidence to support or refute it. Simulating the reaction using computer models may provide some insights but does not directly test the mechanism. Comparing the reaction to similar known reactions can provide some context but does not directly test the proposed mechanism. Publishing the mechanism in a scientific journal is important for sharing findings but does not constitute a test of the mechanism itself.

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