Nursing Elites

1. Which structure in the digestive system absorbs the most nutrients?

• A. Stomach
• B. Small intestine
• C. Large intestine
• D. Esophagus

Correct answer: B

Rationale: The small intestine is the primary site where the absorption of nutrients from digested food occurs. Its large surface area, specialized cells, and villi play key roles in maximizing nutrient absorption, making it the structure in the digestive system that absorbs the most nutrients. The stomach's main function is to break down food with acid and enzymes, not absorb nutrients. The large intestine primarily absorbs water and electrolytes, not nutrients. The esophagus is a muscular tube that connects the throat with the stomach and does not play a role in nutrient absorption.

2. What type of reaction is represented by the following equation: Fe2O3 (s) + 3H2 (g) -> 2Fe (s) + 3H2O (g)?

• A. Combustion
• B. Decomposition
• C. Single displacement
• D. Redox reaction

Correct answer: C

Rationale: The correct answer is C: Single displacement. This reaction is a single displacement reaction because the iron (Fe) in Fe2O3 is displaced by the hydrogen (H) in H2 to form Fe and H2O. In single displacement reactions, one element replaces another in a compound. Choice A, Combustion, involves a reaction with oxygen typically producing heat, light, and often a flame. Choice B, Decomposition, is when a compound breaks down into simpler substances. Choice D, Redox reaction, involves both reduction and oxidation reactions happening simultaneously, which is not the case in the provided equation.

3. What is the primary function of platelets in the blood?

• A. To carry oxygen
• B. To clot blood
• C. To fight infection
• D. To transport nutrients

Correct answer: B

Rationale: The correct answer is B: 'To clot blood.' Platelets play a crucial role in the clotting process, forming a plug at the site of blood vessel injury to prevent excessive bleeding. While red blood cells carry oxygen, white blood cells fight infection, and nutrients are transported by plasma, platelets are specifically responsible for blood clotting. Choice A is incorrect because red blood cells are responsible for carrying oxygen. Choice C is incorrect because white blood cells are primarily involved in fighting infection. Choice D is incorrect as the transport of nutrients is mainly carried out by plasma, not platelets.

4. Which of the following is true regarding T cells?

• A. They are only seen in individuals with leukemia.
• B. They are a specialized type of white blood cell.
• C. They mature in the thymus.
• D. They play a role in the immune response.

Correct answer: D

Rationale: The correct answer is D: T cells are a specialized type of white blood cell that play a crucial role in the immune response. They are produced in the bone marrow and mature in the thymus gland. T cells help coordinate and regulate the immune response to pathogens and foreign substances by interacting with other immune cells. Choices A, B, and C are incorrect. T cells are not exclusively seen in individuals with leukemia; they are a normal component of the immune system found in healthy individuals. While it is true that T cells are a specialized type of white blood cell, the key characteristic being tested in this question is their role in the immune response. Lastly, T cells do mature in the thymus, but this alone does not encompass the full scope of their function in the immune system.

5. What are the differences between RNA and DNA?

• A. Both have the same structure and function.
• B. RNA is single-stranded, while DNA is double-stranded.
• C. RNA contains ribose sugar, while DNA contains deoxyribose sugar.
• D. RNA has adenine and guanine, while DNA has thymine and cytosine.

Correct answer: B

Rationale: A) This statement is incorrect. RNA and DNA have different structures and functions. RNA is involved in protein synthesis and other cellular processes, while DNA stores genetic information. B) This statement is correct. RNA is typically single-stranded, while DNA is double-stranded, forming a double helix structure. C) This statement is correct. RNA contains ribose sugar in its backbone, while DNA contains deoxyribose sugar. D) This statement is incorrect. RNA contains adenine, guanine, cytosine, and uracil, while DNA contains adenine, guanine, cytosine, and thymine. Choice B is the correct answer as it accurately describes one of the key differences between RNA and DNA, emphasizing their structural disparity in terms of single-strandedness for RNA and double-strandedness for DNA. Choices A, C, and D contain inaccuracies regarding the structural and compositional distinctions between RNA and DNA, making them incorrect choices.

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