Nursing Elites

1. What is the building block of DNA?

• A. Amino acid
• B. Nucleotide
• C. Phosphate group
• D. Fatty acid

Correct answer: B

Rationale: - Amino acids are the building blocks of proteins, not DNA. - Nucleotide is the correct building block of DNA. A nucleotide consists of a sugar (deoxyribose in DNA), a phosphate group, and a nitrogenous base (adenine, thymine, cytosine, or guanine). - The option 'C) Phosphate group' is incorrect as it is only part of a nucleotide, not the complete building block of DNA. - Fatty acids are not the building blocks of DNA; they are a type of lipid molecule.

2. The tonsils and adenoids are part of the lymphatic system located in the:

• A. Chest cavity
• B. Abdominal cavity
• C. Head and neck region
• D. Pelvic cavity

Correct answer: C

Rationale: The tonsils and adenoids are lymphatic tissues located in the head and neck region, specifically in the throat area. They are essential components of the immune system, acting as the first line of defense against infections that can enter through the nose and mouth. The tonsils are situated at the back of the throat, while the adenoids are positioned high in the throat behind the nose. Choices A, B, and D are incorrect as they do not correspond to the anatomical location of the tonsils and adenoids. Therefore, the correct answer is the head and neck region.

3. How much sugar is in a 1 M solution of sugar water?

• A. 1 L of water
• B. 100 mL of solution
• C. Every 100 g of water
• D. It depends on the type of sugar

Correct answer: B

Rationale: A 1 M solution of sugar water contains 1 mole of sugar in 1 liter of solution. Since 1 M (molar) solution means there is 1 mole of solute (sugar) dissolved in 1 liter of solvent (water), the correct answer is 100 mL of solution. Choice A, '1 L of water,' is incorrect because it does not specify the total volume of the solution. Choice C, 'Every 100 g of water,' is incorrect as it focuses on the weight of water, not the volume of the solution. Choice D, 'It depends on the type of sugar,' is incorrect since the concentration of a 1 M solution is standardized and does not vary based on the type of sugar used.

4. How is blood pressure controlled by the body?

• A. By adjusting heart rate only
• B. By regulating blood volume
• C. By baroreceptors and hormones
• D. By adjusting body temperature

Correct answer: C

Rationale: Blood pressure is controlled by baroreceptors located in the aortic arch and carotid arteries that detect changes in blood pressure levels. When blood pressure is high, these receptors signal for adjustments to lower it. Additionally, hormones such as renin from the kidneys are released when blood pressure drops, further aiding in blood pressure regulation. Choice A is incorrect because blood pressure regulation involves more than just adjusting heart rate; it also includes vasodilation and vasoconstriction. Choice B is incorrect as while blood volume can impact blood pressure, it is not the primary mechanism of blood pressure control. Choice D is incorrect as body temperature regulation is a separate physiological process and not directly related to blood pressure control.

5. 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.

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