Nursing Elites

1. What happens when a protein unfolds?

• A. Activation
• B. Denaturation
• C. Renaturation
• D. Folding

Correct answer: B

Rationale: Rationale: - Activation (Option A) refers to the process of initiating or increasing the activity of a molecule, such as an enzyme. Protein unfolding does not involve activation. - Denaturation (Option B) is the correct answer. Denaturation refers to the process by which a protein loses its three-dimensional structure, leading to the disruption of its function. This can be caused by factors such as heat, pH changes, or chemicals. - Renaturation (Option C) is the process by which a denatured protein regains its native structure and function. Protein unfolding is the opposite of renaturation. - Folding (Option D) is the process by which a protein assumes its functional three-dimensional structure. Unfolding is the reverse process of folding, not folding itself.

2. Which phenomenon describes the bending of light as it travels from one medium to another with differing densities?

• A. Reflection
• B. Refraction
• C. Diffraction
• D. Dispersion

Correct answer: B

Rationale: The correct answer is B: Refraction. Refraction is the phenomenon that describes the bending of light as it travels from one medium to another with differing densities. When light passes from one medium to another, such as from air to water, its speed changes, causing it to bend. This bending of light is what we observe when a pencil appears bent in a glass of water. Reflection, on the other hand, is the bouncing back of light when it hits a surface. Diffraction refers to the bending of light around obstacles, and dispersion is the separation of light into its different colors. Therefore, in this case, refraction is the most appropriate term to describe the bending of light as it moves between media with different densities.

3. Which of the following substances is an example of an acidic gas?

• A. Nitrogen (Nâ‚‚)
• B. Carbon dioxide (COâ‚‚)
• C. Sulfur dioxide (SOâ‚‚)
• D. Oxygen (Oâ‚‚)

Correct answer: C

Rationale: Sulfur dioxide is an acidic gas. The other choices are either neutral or basic gases.

4. Which of the following is a property of amphiprotic substances?

• A. React with acids only
• B. React with bases only
• C. Can act as both acids and bases
• D. Are inert in chemical reactions

Correct answer: C

Rationale: Amphiprotic substances can donate or accept a proton, so they can act as both acids and bases. The other choices do not accurately describe amphiprotic substances.

5. Which of the following reagents can be used to convert a primary alcohol to an alkyl halide?

• A. HI
• B. H2O
• C. NaOH
• D. SOCl2

Correct answer: D

Rationale: The correct answer is D: SOCl2. SOCl2, also known as thionyl chloride, is commonly used to convert primary alcohols to alkyl halides through an SN2 mechanism. Thionyl chloride reacts with the alcohol to form an alkyl chloride, replacing the hydroxyl group. Option A, HI (hydroiodic acid), is typically used to convert alcohols to alkyl iodides, while option B, H2O (water), and option C, NaOH (sodium hydroxide), are not reagents suitable for this specific transformation. Therefore, SOCl2 is the most appropriate reagent for converting a primary alcohol to an alkyl halide.

6. Which element shares the same group (family) on the periodic table with helium (He)?

• A. Neon (Ne)
• B. Boron (B)
• C. Carbon (C)
• D. Oxygen (O)

Correct answer: A

Rationale: Neon (Ne). Both He and Ne belong to Group 18 (Noble Gases) due to their complete and stable outer electron shells.

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