Nursing Elites

1. Which of the following substances is an example of an acidic gas?

• A. Nitrogen (Nâ‚‚)
• B. Carbon dioxide (COâ‚‚)
• C. Sulfur dioxide (SOâ‚‚)
• D. Oxygen (Oâ‚‚)

Correct answer: C

Rationale: The correct answer is C, Sulfur dioxide (SOâ‚‚). Sulfur dioxide is an acidic gas because when dissolved in water, it forms sulfurous acid, which imparts acidic properties. Nitrogen (Nâ‚‚), carbon dioxide (COâ‚‚), and oxygen (Oâ‚‚) are not considered acidic gases. Nitrogen is a neutral gas, carbon dioxide forms a weakly acidic solution when dissolved in water, and oxygen is a neutral gas.

2. Which organelle provides energy for cellular functions?

• A. Nucleus
• B. Cell membrane
• C. Mitochondria
• D. Cytoplasm

Correct answer: C

Rationale: The correct answer is C, Mitochondria. Mitochondria are often referred to as the powerhouse of the cell as they produce energy in the form of ATP through cellular respiration. This process is essential for various cellular functions, making mitochondria crucial for energy production within the cell. Choice A, Nucleus, is incorrect as the nucleus is responsible for housing the cell's genetic material and controlling cellular activities but not for energy production. Choice B, Cell membrane, is incorrect as it is primarily involved in maintaining cell integrity and regulating the passage of substances in and out of the cell, not in energy production. Choice D, Cytoplasm, is incorrect as it is the jelly-like substance that fills the cell and is the site of many metabolic pathways, but it is not the specific organelle responsible for energy production.

3. A ball is thrown upwards. Which of the following statements is TRUE about its potential energy and kinetic energy at the peak of its trajectory?

• A. Both potential and kinetic energy are zero.
• B. Potential energy is maximum and kinetic energy is minimum.
• C. Potential energy is minimum and kinetic energy is maximum.
• D. Both potential and kinetic energy remain constant.

Correct answer: B

Rationale: At the peak of its trajectory, the ball momentarily stops moving before falling back down. This means its kinetic energy is at a minimum because it has come to a stop. At the same time, its potential energy is at a maximum because it is at the highest point in its trajectory, where it has the most potential to fall and convert that potential energy into kinetic energy as it descends. Choice A is incorrect because at the peak, the ball still has potential energy due to its height. Choice C is incorrect because kinetic energy is at a minimum when the ball is momentarily at rest. Choice D is incorrect because the energy conversion between potential and kinetic energy occurs at different points in the trajectory.

4. What is the role of transfer RNA (tRNA) in protein synthesis?

• A. Transcribes DNA into mRNA
• B. Decodes the genetic code on mRNA
• C. Carries specific amino acids to the ribosomes
• D. Modifies the structure of proteins

Correct answer: C

Rationale: A) Transcribes DNA into mRNA: This is the function of RNA polymerase, not transfer RNA (tRNA). tRNA is involved in protein synthesis, not transcription. B) Decodes the genetic code on mRNA: This is the function of tRNA during translation. tRNA molecules carry specific amino acids and recognize the codons on mRNA, ensuring the correct amino acid is added to the growing polypeptide chain. C) Carries specific amino acids to the ribosomes: This is the primary role of tRNA in protein synthesis. Each tRNA molecule is specific for a particular amino acid and carries it to the ribosome, where it is added to the growing protein chain. D) Modifies the structure of proteins: This is not a function of tRNA. Protein modification can occur after translation is complete and involves other cellular processes and molecules.

5. Which structure in the respiratory system serves as the 'windpipe' that conducts air from the larynx to the bronchi?

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

Correct answer: A

Rationale: The correct answer is the trachea. The trachea, commonly referred to as the 'windpipe,' is a vital structure in the respiratory system that connects the larynx to the bronchi. It is made up of cartilage rings that provide structural support, preventing collapse and ensuring the unobstructed flow of air into the lungs. The trachea plays a crucial role in facilitating the passage of air from the upper respiratory tract to the lower respiratory tract. The larynx is responsible for sound production and is located above the trachea. The bronchi are the two main branches that lead from the trachea into the lungs, further branching into smaller airways. Alveoli are the tiny air sacs where gas exchange occurs in the lungs, but they are not the structure that serves as the 'windpipe' for air passage in the respiratory system.

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