Nursing Elites

1. Autoimmune diseases occur when the immune system mistakenly attacks healthy body tissues. What is a potential cause of autoimmune diseases?

• A. Deficiency in essential vitamins and minerals
• B. Exposure to environmental toxins
• C. Breakdown in immune cell self-tolerance mechanisms
• D. All of the above

Correct answer: C

Rationale: Autoimmune diseases result from a breakdown in immune cell self-tolerance mechanisms, leading to the immune system mistakenly attacking healthy body tissues. While deficiencies in essential vitamins and minerals or exposure to environmental toxins can impact overall health, they are not direct causes of autoimmune diseases. Deficiency in essential vitamins and minerals may weaken the immune system, making it more susceptible to various health issues but does not directly cause autoimmune diseases. Exposure to environmental toxins can trigger immune responses, but autoimmune diseases specifically stem from the breakdown of self-tolerance mechanisms within immune cells. Therefore, the correct answer is a breakdown in immune cell self-tolerance mechanisms.

2. What is the role of the large intestine in the digestive system?

• A. To break down proteins
• B. To absorb water and form feces
• C. To digest fats
• D. To neutralize stomach acid

Correct answer: B

Rationale: The correct answer is B. The large intestine plays a crucial role in absorbing water from indigestible food matter and forming feces for elimination. Choice A is incorrect because the breakdown of proteins primarily occurs in the stomach and small intestine. Choice C is incorrect as the digestion of fats primarily occurs in the small intestine. Choice D is incorrect as neutralizing stomach acid is mainly the function of the stomach lining and not the large intestine.

3. What is the process by which ribosomes use transcribed RNA to assemble the required protein?

• A. Translation
• B. Transcription
• C. Replication
• D. Duplication

Correct answer: A

Rationale: Translation is the correct process where ribosomes decode mRNA to synthesize proteins, following the sequence of codons in the mRNA. During translation, ribosomes use the transcribed RNA (mRNA) as a template to assemble amino acids into a protein according to the genetic code carried by the mRNA. Choice B, Transcription, is incorrect as it is the process of synthesizing mRNA from a DNA template. Choice C, Replication, is also incorrect as it involves the duplication of DNA to produce an identical copy. Choice D, Duplication, is not a biological term related to protein synthesis, making it an incorrect choice.

4. How many moles of water are produced when 0.5 moles of methane (CH4) react with excess oxygen?

• A. 0.5 moles
• B. 1 mole
• C. 2 moles
• D. 3 moles

Correct answer: B

Rationale: The balanced chemical equation for the combustion of methane is: CH4 + 2O2 -> CO2 + 2H2O. This equation shows that 1 mole of methane produces 2 moles of water. Therefore, when 0.5 moles of methane react, they will produce 1 mole of water. The ratio of water to methane is 2:1, meaning that for every mole of methane that reacts, it produces 2 moles of water. Since only 0.5 moles of methane are reacting, the amount of water produced will be half of what would be produced if 1 mole of methane reacted, resulting in 1 mole of water being produced. Choice A is incorrect because it does not consider the stoichiometry of the reaction. Choices C and D are incorrect as they do not align with the balanced chemical equation and the stoichiometric ratios involved in the reaction.

5. The critical angle is defined as the minimum angle of incidence in a denser medium for which light undergoes:

• A. Total internal reflection
• B. Continued refraction
• C. Specular reflection
• D. Increased dispersion

Correct answer: A

Rationale: The critical angle is the minimum angle of incidence in a denser medium at which light undergoes total internal reflection instead of refraction. This phenomenon occurs when light travels from a denser medium to a less dense medium, and the angle of incidence is greater than the critical angle. Total internal reflection is a crucial concept in optics and is utilized in various applications such as fiber optics and prisms. Choice B, 'Continued refraction,' is incorrect as the critical angle specifically marks the point at which total internal reflection occurs, not continued refraction. Choice C, 'Specular reflection,' does not accurately describe the phenomenon associated with the critical angle. Choice D, 'Increased dispersion,' is unrelated to the concept of the critical angle and does not describe the behavior of light at this specific point.

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