Nursing Elites

1. What is the primary function of ribosomes in the cell?

• A. To synthesize lipids and other cellular components
• B. To package and transport proteins
• C. To break down macromolecules
• D. To translate mRNA into proteins

Correct answer: D

Rationale: Ribosomes are cellular organelles responsible for protein synthesis. They read the genetic information encoded in messenger RNA (mRNA) and use this information to assemble amino acids into a specific sequence, forming a protein. This process is known as translation and is essential for the production of proteins that carry out various functions in the cell. Options A, B, and C are incorrect as they do not accurately describe the primary function of ribosomes. Choice A is incorrect because the synthesis of lipids and other cellular components is not the primary function of ribosomes. Choice B is incorrect as packaging and transporting proteins are functions typically associated with the endoplasmic reticulum and Golgi apparatus. Choice C is incorrect because ribosomes do not break down macromolecules; instead, they are involved in building proteins from amino acids.

2. Which of the following are the products of anaerobic respiration in humans?

• A. Ethyl alcohol and CO2
• B. Ethyl alcohol only
• C. Lactic acid and CO2
• D. Lactic acid only

Correct answer: C

Rationale: During anaerobic respiration in humans, lactic acid and CO2 are produced. Choice A, 'Ethyl alcohol and CO2,' is incorrect because ethyl alcohol is not a product of anaerobic respiration in humans. Choice B, 'Ethyl alcohol only,' is incorrect as ethyl alcohol is not a product of anaerobic respiration in humans. Choice D, 'Lactic acid only,' is incorrect because CO2 is also a product of anaerobic respiration in humans.

3. Identify the spectator ions in the reaction: 2KCl + Pb(NO3)2 → 2KNO3 + PbCl2.

• A. K+ and NO3-
• B. K+ and Cl-
• C. Pb2+ and NO3-
• D. Pb2+ and Cl-

Correct answer: B

Rationale: - In the reaction, potassium ions (K+) and chloride ions (Cl-) are present on both sides of the equation. They are not involved in the formation of the products and remain unchanged. - Lead ions (Pb2+) and nitrate ions (NO3-) are involved in the formation of the products potassium nitrate (KNO3) and lead(II) chloride (PbCl2). - Therefore, the spectator ions in this reaction are K+ and Cl-.

4. How does sunscreen protect the skin from harmful ultraviolet (UV) rays?

• A. By reflecting UV rays away from the skin
• B. By absorbing UV rays and converting them to heat
• C. By blocking UV rays completely
• D. By stimulating melanin production

Correct answer: B

Rationale: Sunscreen works by absorbing UV rays and converting them to heat. This mechanism helps to prevent the UV rays from penetrating the skin and causing damage such as sunburn, premature aging, and skin cancer. Reflecting UV rays away from the skin (option A) is not the primary function of sunscreen. While sunscreen does block UV rays, it does not do so completely (option C) as some UV rays may still penetrate the skin. Sunscreen does not stimulate melanin production (option D) as a means of protecting the skin from UV rays.

5. What happens to the diaphragm during inspiration?

• A. It moves upward
• B. It moves downward
• C. It expands
• D. It contracts and moves downward

Correct answer: D

Rationale: During inspiration, the diaphragm contracts and moves downward. This action increases the volume of the thoracic cavity, which lowers the air pressure inside the lungs, allowing air to flow in. The downward movement and contraction of the diaphragm create the necessary space for the lungs to expand and fill with air. Choice A, 'It moves upward,' is incorrect as the diaphragm moves downward. Choice B, 'It moves downward,' is partially correct but misses the contraction aspect. Choice C, 'It expands,' is incorrect as the diaphragm itself does not expand during inspiration. Therefore, choice D, 'It contracts and moves downward,' is the most accurate description of the diaphragm's action during inspiration.

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