Nursing Elites

1. Which of the following nucleic acids carries amino acids to organelles called ribosomes, where the amino acids are linked one by one to produce a polypeptide?

• A. DNA
• B. mRNA
• C. rRNA
• D. tRNA

Correct answer: D

Rationale: tRNA is the correct answer as it carries amino acids to the ribosomes during protein synthesis. Transfer RNA (tRNA) plays a crucial role in protein synthesis by bringing specific amino acids to the ribosome according to the mRNA sequence. Once at the ribosome, the amino acids are linked together to form a polypeptide chain. This process is essential for the creation of proteins in the cell, highlighting the significance of tRNA in the translation process. Choice A, DNA, is incorrect as DNA does not directly participate in protein synthesis. Choice B, mRNA, is incorrect as mRNA carries the genetic information from DNA to the ribosome but does not directly carry amino acids. Choice C, rRNA, is incorrect as ribosomal RNA is a component of the ribosome structure and is involved in protein synthesis but does not carry amino acids like tRNA.

2. Which of the following is a function of the kidneys?

• A. To produce digestive enzymes
• B. To filter waste from the blood
• C. To produce white blood cells
• D. To produce red blood cells

Correct answer: B

Rationale: The correct answer is B: 'To filter waste from the blood.' The kidneys are vital organs responsible for filtering waste products from the blood, regulating fluid and electrolyte balance, and producing urine. Choice A is incorrect because the production of digestive enzymes primarily occurs in the pancreas and salivary glands. Choice C is incorrect as the production of white blood cells mainly takes place in the bone marrow and lymphatic system. Choice D is incorrect as the production of red blood cells occurs in the bone marrow.

3. What is the main function of calcitonin, a hormone produced by the thyroid gland?

• A. Stimulate metabolism and heat production
• B. Increase calcium absorption from the intestines
• C. Enhance bone growth and development
• D. Lower blood calcium levels

Correct answer: D

Rationale: Calcitonin is a hormone produced by the thyroid gland that primarily functions to lower blood calcium levels. It achieves this by inhibiting bone breakdown and promoting calcium excretion by the kidneys. Therefore, the correct answer is D as it reflects the main role of calcitonin in calcium homeostasis. Choices A, B, and C are incorrect as they do not align with the primary function of calcitonin. Calcitonin does not stimulate metabolism and heat production (Choice A), increase calcium absorption from the intestines (Choice B), or enhance bone growth and development (Choice C).

4. Which of the following structures has the lowest blood pressure?

• A. Arteries
• B. Arterioles
• C. Venules
• D. Veins

Correct answer: D

Rationale: Veins have the lowest blood pressure among the listed structures. Blood pressure decreases as blood flows from arteries to arterioles, then to venules, and finally to veins. Veins return blood to the heart under low pressure because they have thinner walls and larger lumens compared to arteries and arterioles. This anatomical difference allows veins to accommodate a greater volume of blood without a significant rise in pressure. Arteries have the highest blood pressure to propel blood away from the heart, followed by arterioles which regulate blood flow to capillaries. Venules collect blood from capillaries and connect to veins, which then carry blood back to the heart at a lower pressure.

5. When is work done on an object?

• A. Only when the object's velocity changes
• B. Only when a force is applied to the object
• C. Whenever there is a force exerted on the object causing displacement
• D. Only when the object is lifted vertically

Correct answer: C

Rationale: Work is done on an object whenever a force causes displacement in the object's position. According to the work-energy principle, work is calculated as the force applied multiplied by the distance the object moves in the direction of the force. Therefore, work can occur whenever there is a force exerted on the object resulting in displacement, regardless of whether the object's velocity changes or it is lifted vertically. Choice A is incorrect because work can be done even without a change in velocity. Choice B is incorrect as work requires both force and displacement, not just the application of force. Choice D is incorrect because work is not limited to vertical lifting; it can happen in any direction as long as there is a force causing displacement.

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