Nursing Elites

1. Which of the following is a chief difference between evaporation and boiling?

• A. Liquids boil only at the surface, while they evaporate equally throughout the liquid.
• B. Evaporating substances change from liquid to gas, while boiling substances change from gas to liquid.
• C. Evaporation can happen below a liquid's boiling point.
• D. Evaporation happens in nature, while boiling is a man-made phenomenon.

Correct answer: C

Rationale: The chief difference between evaporation and boiling is that evaporation can happen below a liquid's boiling point, while boiling only occurs at the liquid's boiling point. Evaporation is the process of a liquid turning into a gas at any temperature, while boiling specifically refers to the rapid vaporization that occurs when a liquid reaches its boiling point. Choice A is incorrect because liquids evaporate throughout the liquid, not just at the surface. Choice B is incorrect as evaporating substances change from liquid to gas, while boiling substances change from liquid to gas. Choice C is incorrect as boiling is not a man-made phenomenon; in fact, it is a natural process based on temperature changes. Choice D is incorrect because evaporation can happen naturally and is not limited to man-made processes.

2. What are the building blocks of proteins?

• A. Sugars
• B. Fatty acids
• C. Amino acids
• D. Nucleotides

Correct answer: C

Rationale: Proteins are macromolecules made up of long chains of amino acids. Amino acids are the building blocks of proteins and are linked together through peptide bonds to form polypeptide chains, which then fold into specific three-dimensional structures to carry out various functions in the body. Sugars (choice A) are the building blocks of carbohydrates, fatty acids (choice B) are the building blocks of lipids, and nucleotides (choice D) are the building blocks of nucleic acids like DNA and RNA. Therefore, the correct answer is amino acids (choice C), as they are specifically responsible for protein synthesis.

3. Which hormone, produced by the pituitary gland, stimulates the production of milk in mammary glands during breastfeeding?

• A. Growth hormone (GH)
• B. Thyroid-stimulating hormone (TSH)
• C. Prolactin
• D. Follicle-stimulating hormone (FSH)

Correct answer: C

Rationale: Prolactin is the hormone produced by the pituitary gland that stimulates the production of milk in mammary glands during breastfeeding. It plays a crucial role in lactation by promoting the development of mammary tissue and the production of milk. Growth hormone (GH), thyroid-stimulating hormone (TSH), and follicle-stimulating hormone (FSH) do not directly stimulate milk production in mammary glands. Therefore, choices A, B, and D are incorrect in the context of stimulating milk production during breastfeeding.

4. What is the 3D structure of a protein called?

• A. Tertiary structure
• B. Secondary structure
• C. Primary structure
• D. Quaternary structure

Correct answer: A

Rationale: - Primary structure refers to the linear sequence of amino acids in a protein. - Secondary structure refers to local folded structures within a protein, such as alpha helices and beta sheets. - Tertiary structure is the overall 3D shape of a protein, which is determined by interactions between amino acid side chains and the environment. - Quaternary structure refers to the arrangement of multiple protein subunits in a protein complex. Therefore, the 3D structure of a protein is called the tertiary structure because it represents the overall folding of the protein into a specific shape.

5. What does half-life refer to?

• A. Radioactive intensity to completely disappear
• B. The number of neutrons in a nucleus to double
• C. The number of protons in a nucleus to change
• D. An isotope to decay by half of its initial quantity

Correct answer: D

Rationale: Half-life refers to the time it takes for half of the radioactive atoms in a sample to decay. This means that after one half-life, half of the initial quantity of the radioactive substance will have decayed. Choice A is incorrect because radioactive intensity doesn't completely disappear during half-life. Choice B is incorrect as half-life doesn't refer to the number of neutrons doubling. Choice C is incorrect as half-life doesn't relate to the number of protons changing.

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